How is the yolk sac formed? What is the function of the yolk sac?

1 year ago
Biology

The yolk sac is formed from the covering of the vitellus by some cells originated from the primitive gut. The yolk sac stores vitellus, the main nourishment source of non-placental embryos.

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Dipti KC
Dipti KC
May 26, 2023
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274. What is reproductive isolation?

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278. What are the fundamental similarities and differences between lamarckism and darwinism?

279. How did Darwin reach the principle of natural selection from the observation of differences among individuals of the same species?

280. How did the industrial revolution in England offer an example of natural selection?

281. What is the mechanism described by Darwin that eliminates species less adapted to environmental conditions?

282. Who was Charles Darwin?

283. What is lamarckism?

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285. Historically what were the two main evolutionary theories?

286. How does the study of fossils strengthen the theory of evolution?

287. What are fossils?

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289. What is fixism?

290. What is the main theory opposed to evolution?

291. What is the problem that the theory of evolution and its rival theories try to solve?

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293. How did the first fermenting autotrophs appeared? What about the first aerobic beings?

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295. How have prokaryotic cells given origin to aerobic eukaryotic cells and to photosynthetic aerobic eukaryotic cells?

296. What is the evolutionary origin of the internal membranous organelles of the cell?

297. How could coacervates have facilitated the emergence of life on earth?

298. What are coacervates?

299. How can coacervates be formed of phospholipids or polypeptides?

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301. Before the emergence of life of what gases was the earth's primitive atmosphere constituted?

302. What is the most accepted hypothesis about the origin of life on earth? How does it compare to the other main hypotheses?

303. What are the main constituents of the earth's atmosphere in our time?

304. What is the heterotrophic hypothesis on the origin of life?

305. What is panspermia?

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307. What is the autotrophic hypothesis on the origin of life?

308. What is the spontaneous generation hypothesis?

309. Historically how has the origin of life on earth been explained?

310. When did life appear on earth?

311. How old is the universe?

312. How old is the earth?

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314. What is the fact of Molecular Biology on which DNA fingerprint is based?

315. Why are the recombinant DNA technology and the nucleus transplantation technology still dangerous?

316. What is PCR? How does PCR works?

317. What is cloning?

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319. How is genetic engineering used to create bacteria capable of producing human insulin?

320. What are plasmids?

321. What are DNA ligases? How do these enzymes participate in the recombinant DNA technology?

322. At the present level of the biotechnology what are the main techniques of genetic engineering?

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324. What is genetic engineering?

325. What is biotechnology?

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327. What are the penetrance and the expressivity of a gene?

328. What is the mathematical expression of the genetic equilibrium for genes with two alleles? Is this statistical distribution the same as the statistical distribution of the respective phenotypes?

329. An hypothesis for the extinction of the dinosaurs is that the earth had been hit by a gigantic meteor that caused the death of those big reptiles. In that case the entire genetic pool of those animals has been destroyed, invalidating the Hardy-Weinberg equilibrium. In Genetics what is this type of gene frequency change called?

330. How is the early diagnosis of genetic diseases usually done?

331. What is genetic equilibrium?

332. What is allele frequency?

333. What is consanguineal marriage? Why is the appearing of genetic disease more probable in the offspring of a consanguineal marriage?

334. What are some diseases or genetic abnormalities caused by dominant genes? Why are severe dominant genetic diseases rarer than recessive ones?

335. How do the repairing enzymes of the genetic system act?

336. How are mutagenic agents related to cancer incidence in a population? Is cancer a disease transmitted to the individual offspring?

337. What are some diseases or genetic abnormalities caused by recessive genes?

338. How do genetic mutations influence biological diversity?

339. What are mutagenic agents?

340. Does every gene mutation cause alteration in the protein the gene normally codifies?

341. What are genetic mutations?

342. Do all genetic diseases result from alteration in the number of chromosomes of the cells?

343. In general what is the cause of the aneuploidies?

344. How are genetic diseases classified?

345. What is aneuploidy? What are the conditions caused by the aneuploidies?

346. Why in the preparation of a karyotype analysis is the use of a substance like colchicine interesting?

347. Which type of genetic disease can be identified from the visual analysis of the number of chromosomes present in a karyotype?

348. What is the karyotype found in Down syndrome?

349. What is karyotype?

350. What is the MN blood system? What is the pattern of genetic inheritance of the MN blood system?

351. How can the hemolytic disease of the newborn be prevented?

352. What is the logic of the transfusional compatibility concerning the Rh blood group system?

353. How does the immune process that causes the hemolytic disease of the newborn take place?

354. What are the inheritance and dominance patterns of the Rh blood system?

355. What is the Rh typing of the mother and of the fetus in the hemolytic disease of the newborn?

356. How is the blood typing concerning the ABO system and the Rh usually done?

357. What is the Rh factor?

358. What is blood typing?

359. Is ABO blood compatibility enough for the safety of blood transfusion?

360. How are the antibodies against the Rh factor formed?

361. Is it possible to perform investigation of natural paternity, maternity or brotherhood and sisterhood using the ABO blood typing?

362. What are universal donors and universal recipients concerning the ABO blood system?

363. What are the genotypes and respective blood types of the ABO system?

364. What is the type of genetic inheritance that determines the ABO blood group system? What are the relations of dominance among the involved alleles?

365. What is the logic of the transfusional compatibility concerning the ABO blood group system?

366. What are the antigens and the respective antibodies of the ABO blood group system?

367. What are the antigens and antibodies of each blood type of the ABO blood system?

368. Why is the determination of the blood types of the donor and of the recipient important in transfusions?

369. What are the blood types of the ABO blood system?

370. What are the main human blood group systems?

371. What is sex-influenced dominance?

372. What are holandric genes?

373. What is the clinical manifestation of the disease known as daltonism?

374. Are sex-linked diseases associated only to genes of the X chromosome?

375. Is it possible for any son of a couple formed by a hemophilic man (XhY) and a nonhemophilic noncarrier (XX) woman to be hemophilic?

376. What is the type of genetic inheritance of daltonism? Is daltonism more frequent in men or in women? What is the physiological explanation for the daltonism?

377. Why is it rare to find hemophilic women?

378. What are all possibilities of genotypes and phenotypes formed in the combination of alleles responsible for the production of factor VIII?

379. What is the clinical deficiency presented by hemophilic people? What is the genetic cause of that deficiency?

380. How many alleles of genes that condition X-linked traits do female and male individuals respectively present?

381. What are X-linked traits?

382. What is the clinical deficiency presented by hemophilic people? What is the genetic cause of that deficiency?

383. Besides the XY system are there other sex determination systems?

384. What is the inactivation of the X chromosome? What is a Barr body?

385. What are the main diseases caused by errors of the number of sex chromosomes in the cells of an individual?

386. Do the genes of the X and Y chromosomes determine only sex characteristics?

387. Is it more indicated for a geneticist desiring to map the X chromosome of the mother of a given family (the researcher does not have access to her DNA, only access to the genetic material of the offspring) to analyze the chromosomes of her daughters or of her sons?

388. Is it possible that an X chromosome of a woman can have come from her father?

389. What are the homologous and the heterologous portions of the human sex chromosomes?

390. How is the genetic determination of sex established in humans?

391. Concerning the sex chromosomes of the XY system which type of gamete do the male and the female individuals respectively produce?

392. Is crossing over important for the diversity of biological evolution?

393. How can the concept of recombination frequency be used in genetic mapping?

394. What is recombination frequency?

395. What is a centimorgan?

396. In genetic recombination by crossing over what is the difference between parental gametes and recombinant gametes?

397. Why does the recombination frequency of genes vary with the distance between them in the chromosome?

398. What is crossing over? How is meiosis related to this phenomenon?

399. Why is drosophila a convenient animal for the study of linked genes?

400. Why is not Mendel’s second law always valid for two or more phenotypical traits of an individual?

401. What is linkage?

402. What is mitochondrial inheritance?

403. Why is sex-linked inheritance an example of nonmendelian inheritance?

404. What is the most probable inheritance pattern of a trait with gaussian proportional distribution of phenotypical forms?

405. How to find the number of pair of alleles involved in polygenic inheritance using the number of phenotypical forms of the trait they condition?

406. What is polygenic inheritance? How does it work?

407. In the hybridization of 2 genes (4 different alleles, 2 of each pair) how does epistasis affect the proportion of phenotypical forms in the F2 generation?

408. What is epistasis? What is the difference between dominant epistasis and recessive epistasis?

409. What are complementary genes? Does this inheritance pattern obey Mendel’s second law?

410. What are multiple alleles? Is there dominance in multiple alleles?

411. What are gene interactions? What are the three main types of gene interactions?

412. What are lethal genes?

413. What is pleiotropy?

414. According to Mendel’s law phenotypical characteristics would be determined by pair of factors (alleles) that separate independently in gametes. What are the main types of inheritances that are exceptions to Mendel’s rules?

415. What is the genetic condition in which the heterozygous individual has different phenotype from the homozygous individual?

416. How is it possible to obtain the probability of emergence of a given genotype formed of more than one pair of different alleles with independent segregation from the knowledge of the parental genotypes?

417. According to Mendel’s second law, in the crossing between homozygous individuals concerning two pairs of nonlinked alleles, AABB x aaBB, what are the genotypical and phenotypical proportions in F1 and F2?

418. Considering independent segregation of all factors, how many types of gametes does a VvXXWwYyzz individual produce? What is the formula to determinate such number?

419. What is the condition for Mendel’s second law to be valid?

420. What are the main conventional symbols and signs used in genetic family trees?

421. What is Mendel’s second law?

422. What is a genetic family tree?

423. What are the three main steps for a good study of a genetic family tree?

424. Why can the crossing of an individual that manifests dominant phenotype with another that manifests recessive phenotype (for the same trait) determine whether the dominant individual is homozygous or heterozygous?

425. Which is the type of gamete produced by a heterozygous individual? What is the genotypical proportion of these gametes?

426. Which is the type of gamete (for a given trait) produced by a dominant homozygous individual? What is the genotypical proportion of these gametes? What about a recessive homozygous individual?

427. In the F2 generation of a hybridization for a given trait conditioned by a pair of alleles T and t, according to Mendel’s first law what are the genotypes of each phenotypical form? How many respectively are the genotypical and phenotypical forms?

428. What is the Mendel’s first law?

429. Considering hybridization in a given trait like the color of the hair of a mammalian species (white/black) conditioned by a pair of different alleles under complete dominance (black dominant, B/ white recessive, w), how can the phenotypical proportion obtained in the F2 generation be explained? What is this proportion?

430. What is meant by saying that in relation to a given trait conditioned by a gene with two different alleles the gametes are always “pure”?

431. Considering hybridization in a trait like the color of the flowers of a given plant species (red/yellow) conditioned by a pair of different alleles in relation to complete dominance (red dominant/ yellow recessive), why in the F1 generation is one of the colors missing?

432. Considering hybridization in a trait like the color of the flowers of a given plant species (red dominant/ yellow recessive) conditioned by a pair of different alleles, what are the phenotypical results of the first generation (F1) and the phenotypical results of the second generation (F2, formed by crossing among F1 genotypes)? What are the phenotypical proportions in F1 and F2?

433. What in Genetics is hybridization?

434. What is monohybridism?

435. Who was Gregor Mendel?

436. Why can it be said that a recessive allele can remain hidden in the phenotype of an individual and revealed only when manifested in homozygosity in the offspring?

437. What is the difference between dominant allele and recessive allele?

438. What is the difference between homozygosity and heterozygosity?

439. Whenever a pair of alleles has different alleles is there dominance between them?

440. For an individual having a genotype formed of two different alleles that condition different varieties of the same phenotypical trait, upon what will the phenotypical feature actually manifested depend?

441. Considering a pair of homologous chromosomes containing a gene having two different alleles how many different genotypes can the individual present?

442. What are some examples of phenotypical characteristics that present two or more varieties and of phenotypical features that do not vary? In relation to the genes correspondent to those characteristics that vary among individuals what can be expected about their alleles?

443. What are the situations in which the environment can alter the genotype of an individual? What is the condition for this type of change to be transmitted to the offspring?

444. Are environmental phenotypical changes transmitted to the offspring?

445. Does the environment exert an influence on the phenotype?

446. What is a genotype? What is the difference between genotype and phenotype?

447. What is a phenotype?

448. Are the alleles of a gene necessarily originated one from the father and the other from the mother? Are there exceptions?

449. What is meant by “gene locus”?

450. How is the concept of chromosome related to the concept of the gene?

451. Is a gene a triplet of consecutive DNA nucleotides?

452. What are alleles of a gene?

453. What is a gene?

454. Why do most plants present opposite phyllotaxis?

455. How do plants classify according to their photoperiodism-based flowering?

456. What is the critical photoperiod? How can the critical photoperiod relate to flowering be experimentally determined?

457. How does the photoperiodism affect the flowering of some plants?

458. What are the plant organs responsible for the perception of light variation? What is the pigment responsible for this perception?

459. What is photoperiodism?

460. What is photoperiod?

461. What are the types of plant geotropisms? Why do the stem and the root present opposite geotropisms?

462. What is thigmotropism?

463. What is phototropism?

464. To which direction does the growth of one side of a stem, branch or root induce the structure to curve?

465. What is the plant hormone remarkable for stimulating flowering and fruit ripening? What are the uses and practical inconveniences of that hormone?

466. What are plant tropisms?

467. What are cytokinins? Where are they made?

468. Are the development and growth of plants only influenced by plant hormones?

469. What are gibberellins? Where are they produced?

470. What happens when the auxin concentration in some structures of the plant is over the action range of the hormone?

471. How do auxins act helping the lateral (secondary) growth of the stem?

472. What is the phenomenon of apical dominance in plants? How can it be artificially eliminated?

473. How do phytohormones help the development of parthenocarpic fruits?

474. Where in plants is a large amount of IAA found?

475. What are synthetic auxins and what are their uses?

476. What are the main natural plant hormones and what are their respective effects?

477. What is indolacetic acid (IAA)?

478. What are plant hormones?

479. What is the plant coleoptile? Why does the removal of the coleoptile extremity disallow plant growth?

480. What is tree girdling? What happens to a plant when that girdle is removed from the stem (below the branches)?

481. What are the forces that make water to flow within the xylem from the roots to the leaves?

482. What is capillarity? How is this phenomenon chemically explained? What is the relevance of capillarity for water transport in plants?

483. What is root pressure?

484. What is the importance of lignin for the xylem formation?

485. Are the xylem and the phloem made of living cells?

486. How do the water absorption volume and the water transpiration volume comparatively vary in plants in a day? What is the final comparative balance of these processes?

487. Is transportation of gases in tracheophytes made through the vascular tissues?

488. When air humidity is high does the plant transpiration increase or lower?

489. How do plants solve the problem of transporting substances throughout their tissues?

490. Is transpiration the only way through which leaves lose water?

491. How has the position of the stomata changed in some plants to prevent excessive water loss by transpiration?

492. Do plants placed under an environment drier than the habitat where they are used to living have an increase or a reduction in the time during which their stomata remain open?

493. Why do some plants adapted to a dry environment open their stomata only at night?

494. How do plants control the opening and the closing of the stomata?

495. What are the elements that constitute the stomata?

496. What are stomata? How do these structures participate in the plant transpiration?

497. What are the main gas exchange organs of the plants? How is the process accomplished?

498. Why do plants need to exchange gases with the environment?

499. What is plant transpiration? What are the two main types of plant transpiration process? Which of them is more significant in volume?

500. Why do roots of many swamp plants have a special morphology?

501. What are secondary roots? In origin how secondary roots differentiate from shoots?

502. What is the root cap?

503. Why does bark often die and break naturally?

504. What are the plant root hairs? Where can they be found and what is their function?

505. Which are the plant tissues that form the plant roots?

506. Which type of plant tissue is cork?

507. What is the leaf cuticle?

508. What is phellogen? What is its function?

509. Which are the plant tissues that cover the stem and the leaves?

510. How can the age of a tree be estimated from the analysis of the rings present on a cross section of its stem?

511. Which are the plant tissues specialized in covering?

512. What are the main plant tissues that form the rings observed on stem sections of some trees?

513. What are the main plant tissues that form the rings observed on stem sections of some trees?

514. What are the plant tissues that constitute the functional structures of the leaf veins?

515. What are vascular bundles? How does the configuration of the vascular bundles within the stem differentiate monocots from dicots?

516. What are the cell types that form the xylem? What are the main features of those cells?

517. What is the vascular cambium? What is its function?

518. Which are the specialized conductive tissues of the plants?

519. What are the cell types that form the phloem? What are the main features of those cells?

520. How are water, mineral salts and food (sugar) transported throughout the plant?

521. Where in the leaves is the photosynthetic tissue often located?

522. Which are the plant tissues responsible for the supporting of the plant?

523. Which is the plant tissue responsible for the filling of the space between other tissues?

524. What is the best identification hypothesis for a plant tissue seen under the microscope having most cells undergoing cell division?

525. What are the main features of the meristematic cells? Why do these cells need to have a high mitotic rate?

526. What are lateral meristems? Where can they be found and which type of plant growth do they promote?

527. Which are the growth tissues of plants? How do they classify and where can they be found?

528. What are apical meristems? Which type of plant growth does this meristem promote?

529. What is the difference between the lateral and the apical buds of the plants?

530. How are the plant tissues classified according to their functions?

531. What are the trends of the gametophyte in the evolution of plants?

532. What is the evolutionary importance of the fruits for the angiosperms?

533. What are infructescences, pseudofruits and parthenocarpic fruits?

534. Why are there plants having single-seeded fruits and plants having fruits with more than one seed?

535. What are the main functions of fruits?

536. What are cotyledons?

537. Are fruits always the flesh part of the “fruits”? Is the edible part of the onion a fruit?

538. How different are the endosperm of gymnosperms and the endosperm of angiosperms?

539. How are fruits formed?

540. From which floral structure do fruits come?

541. What are the typical structures of the seed? What is endosperm?

542. What is dichogamy?

543. After pollination how does fecundation occur in angiosperms? In these plants is fecundation dependent on water?

544. What is the difference between self pollination and cross pollination? Which of these two modes of pollination contributes more to the plant diversity?

545. What is the embryonic sac? Which are the cells that form the embryonic sac? What are their ploidies?

546. How are the male gametophytes and the male gametes formed in angiosperms?

547. How is the female gametophyte formed in angiosperms?

548. How many cellular nuclei does the pollen tube of angiosperms have? What is the ploidy of each of these nuclei?

549. What is pollination? What are the main forms of pollination?

550. What are the main morphological differences between monocot plants and dicot plants?

551. What are the androecium and the gynoecium? What are the other structures of flowers?

552. What are the two main groups into which flowering plants are divided?

553. What are angiosperms, the flowering plants? What is the main feature that distinguishes them from the gymnosperms?

554. How are the gymnosperm seeds formed? What are the ploidies of the structures that compose the seeds?

555. How do fecundation and zygote formation occur in these plants? Do these processes depend on water?

556. How are the female gametes of gymnosperms formed? What is the relationship between this process and the concept of alternation of generations?

557. How are the male gametes of gymnosperms formed? What is the relationship between the pollen grains and the concept of alternation of generations?

558. What is the evolutionary importance of the emergence of seeds in the plant kingdom?

559. What is pollen?

560. What is the life cycle of the gymnosperms?

561. How different are gymnosperms from bryophytes and pteridophytes?

562. In which areas of the globe is gymnosperm abundance noteworthy?

563. What are the main divisions and representing species of the gymnosperms?

564. What is xaxim?

565. What is the lasting form in pteridophytes, the gametophyte or the sporophyte? How can it be compared to bryophytes?

566. Why are pteridophytes more common in humid places?

567. How are gametes formed in the pteridophyte life cycle, by mitosis or meiosis? What is the type of meiosis that occurs in pteridophytes?

568. What is the type of life cycle present in pteridophytes?

569. What is the prothallus of pteridophytes?

570. What are the main parts of ferns?

571. What is the structure of the adult fern within which cells undergoing meiosis can be found?

572. What is the evolutionary importance of pteridophytes?

573. How different are pteridophytes from bryophytes regarding substance transport?

574. Why are pteridophytes better adapted to dry land than bryophytes? Were pteridophytes always less abundant than phanerogamic plants?

575. What are the main representatives of the pteridophytes? Is this plant group cryptogamic or phanerogamic?

576. How is the transport of substances done across the bryophyte tissues? How is this feature related to the general size of these plants?

577. Why can the bryophytes be considered the “amphibians of the plant world”?

578. In general where is the sporophyte positioned in relation to the gametophyte in bryophytes? How does the sporophyte obtain nutrients?

579. What are the main bryophyte groups?

580. What is the life cycle type of bryophytes?

581. What are the main characteristics of the bryophytes?

582. For each of the three types of life cycles what is the respective ploidy of the individual that represents the adult or lasting form?

583. Why is the plant life cycle known as alternation of generations?

584. Do plants present only sexual reproduction?

585. Are gametes always made by meiosis?

586. What are the three basic sexual life cycles studied in Biology? Which of them corresponds to metagenesis? Which of them is the human life cycle?

587. What respectively are zygotic meiosis, gametic meiosis and sporic meiosis?

588. What are the two divisions of the angiosperms?

589. What is the difference between cryptogamic and phanerogamic plants?

590. Do plants have tissue organization and specialized organs?

591. What are the four main groups into which the study of the plants is divided?

592. What is the difference between bryophytes and tracheophytes?

593. How different are animal cells from plant cells?

594. What is the difference between bryophytes and tracheophytes?

595. What are the main cellular features of the beings of the plant kingdom?

596. What are the subkingdoms into which the plant kingdom is divided?

597. What are the endocrine functions of the placenta?

598. Is there a exchange of cells between the mother and the fetus through the placenta?

599. What is the function of the umbilical cord?

600. What are the main substances transferred from the mother to the fetus through the placenta? And from the fetus to the mother?

601. Why can the amnion also be considered an adaptation to terrestrial life?

602. In which type of animals does the placenta exist? What is its main function?

603. What is the difference between amnion and chorion?

604. What is the chorioallantois membrane present in the embryonic development of reptiles and birds? How does this membrane participate in the energetic metabolism of the embryo?

605. Why can the allantois be considered an adaptation to terrestrial life?

606. Are the extraembryonic membranes the same in all vertebrates?

607. Which is the extraembryonic membrane whose function is to store nitrogen wastes of the embryo? Is this function present in placental mammalian embryos?

608. What are the extraembryonic membranes present in vertebrates?

609. What are extraembryonic membranes?

610. What is polyembryony?

611. What are twins? Genetically what are the two types of twins that can be generated?

612. From which germ layer do the liver and the pancreas originate? What are other organs and tissues made from that germ layer?

613. What are histogenesis and organogenesis?

614. From which germ layer do blood cells originate? What are other organs and tissues made from that germ layer?

615. What are somites?

616. From which germ layer do the epidermis and the nervous system originate? What are other organs and tissues made from that germ layer?

617. After the neurula stage and from its ventral portion to the dorsal how can the morphology of the embryo be described?

618. What are pleura, pericardium and peritoneum?

619. How does the embryo turn from gastrula into neurula? How is the neural tube formed? What is the embryonic origin of the nervous system in vertebrates?

620. What is the germ layer from which the coeloms originate?

621. What is the coelom? To which structures do coeloms give birth? Are all animals coelomate?

622. How are animals classified according to the germ layers present in their embryonic development?

623. What is gastrulation? How during gastrulation are the first two germ layers formed? What are these germ layers?

624. What are the three types of germ layers that form tissues and organs in animals?

625. How is the mesoderm (third germ layer) of triploblastic animals formed?

626. After the blastula stage what is the following stage of the embryonic development? What is the passage from blastula to the next stage called?

627. What are the archenteron and the blastopore? What is the stage of the embryonic development in which these structures are formed? What are the destinations of the archenteron and of the blastopore?

628. After the morula stage what is the next stage? What is the morphological feature that defines this stage?

629. What is the function of the vitellus in the vertebrate egg? How are these eggs classified according to the amount of vitellus within them?

630. What are the animal pole and the vegetal pole of the vertebrate egg?

631. What are the cells produced in the first stage of the embryonic development called?

632. What is the cell division during the first stage of the embryonic development called? How is this stage characterized?

633. What are the four initial stages of the embryonic development?

634. What is the cell division process directly related to the embryonic growth?

635. What is the contraceptive mechanism of the IUD?

636. What is parthenogenesis?

637. How is the ovulation date estimated with the control of the woman's body temperature?

638. Generally how does a male animal realize that the female is receptive to copulation?

639. What is the normal duration of the menstrual cycle? How does the calendar contraceptive method work?

640. What are the most common methods of male and female surgical sterilization?

641. Why is the use of condoms not just a contraceptive method but also a health protection behavior?

642. What are the common contraindications of the contraceptive pills?

643. How does the contraceptive diaphragm work? What are the limitations of this contraceptive method?

644. How do contraceptive pills generally work?

645. What is the endocrine function of the placenta?

646. Does the hypophysis- ovaries endocrine axis work in the same way during pregnancy as in non-pregnant women? If pregnancy does not occur how does another menstrual cycle begin?

647. How do hormonal tests to detect pregnancy work?

648. What is tubal pregnancy?

649. What is nidation? In which phase of the menstrual cycle does nidation occur?

650. In general what is the phase of the menstrual cycle when copulation may lead to fecundation?

651. How does the sexual arousal mechanism in women facilitate fecundation?

652. What is the part of the female reproductive system where fecundation occurs?

653. Including main events and hormonal changes how can the menstrual cycle be described?

654. What is the explanation for the bleeding that accompanies menses?

655. In hormonal terms why does menses occur?

656. Which are the phases of the menstrual cycle?

657. How does the hypophysis- corpus luteum negative feedback work? What is the name given to the atrophied corpus luteum after this feedback process?

658. What is the importance of the uterine glycogen- producing glands?

659. How does the female gamete move from the ovary to the uterus?

660. What is the structure into which the follicle is transformed after ovulation? What is the importance of that structure in the menstrual cycle?

661. What are the hormones that promote the release of the female gamete from the follicle and at which day of the menstrual cycle does this phenomenon happen? What is this event called?

662. How long after ovulation must fecundation occur to be effective?

663. What is the relationship between the estrogen level and the LH level in the menstrual cycle? What is the function of LH in the menstrual cycle and when does its blood concentration reach a peak?

664. What event marks the beginning of the menstrual cycle? What is the blood concentration of FSH, LH, estrogen and progesterone in this phase of the cycle?

665. What is the hormone secreted by the growing ovarian follicles? What is the action of that hormone upon the uterus?

666. What are the endocrine glands involved in the menstrual cycle? What are the hormones in action?

667. After menses what is the hormone that influences the maturation of the ovarian follicles?

668. What is the menstrual cycle?

669. What are the anatomical relationships between the organs of the female reproductive system from the external vulva to the ovaries?

670. In which period of life does the formation of gametes begin in women?

671. What is the organ that releases the female gamete under formation? How is this release triggered? What is the organ that collects the released gametes?

672. What are the organs that are part of the female reproductive system?

673. What are the endocrine glands that regulate sexual activity in males? How does this regulation work and what are the involved hormones?

674. After passing the epididymides through which structures do sperm cells go until exteriorization?

675. Concerning reproduction what is the function of the testicles?

676. What is the function of the secretions of the prostate, seminal vesicle and bulbourethral glands in reproduction?

677. What are the organs that are part of the male genital system?

678. Concerning their size and basic morphology how and why do the male and the female gametes differentiate from each other?

679. What are the female pronucleus and the male pronucleus?

680. What is the relationship between the menstrual cycle and ovulation?

681. What is the second polar body?

682. How does the male gamete penetrate the egg cell? How does the female gamete protect itself from the entrance of more gametes after the entrance of the first sperm cell?

683. What is the relation between fecundation and the end of the meiotic process during oogenesis?

684. What is the first polar body? How different is it from the oocyte II?

685. Concerning events during the periods of life how different is the gametogenesis in women and in men?

686. Indicating the name and respective ploidy of each involved cell how can the formation of egg cells from germ cells be described?

687. Why is the cytoplasm of sperm cells very reduced? Why do mitochondria of sperm cells concentrate in the base of the flagellum?

688. What is the function of the flagellum of the sperm cell? How is it formed?

689. What is the difference between spermatocyte II and spermatid?

690. What is the acrosome of the sperm cell? How is it formed?

691. What is the difference between spermatocyte I and spermatocyte II?

692. What is the difference between spermatogonium and spermatocyte I?

693. What is the difference between spermatids and sperm cells? What is the name of the transformation of spermatids into sperm cells?

694. Indicating the name and respective ploidy of each involved cell how can the formation of sperm cells from germ cells be described?

695. What is the type of cell division that allows sexual reproduction? What is gametogenesis?

696. What are gonads? What are the male and the female gonads in humans?

697. What is the name of the cells capable of making gametes? What is the ploidy of these gamete-forming cells?

698. What are gametes?

699. What is the name given to conditions in which the own immune system of the individual is the agent of diseases? What are some examples of these conditions?

700. What is the DNA vaccine?

701. Why are vaccines used in the prevention but not in the treatment of infections? Why can antivenom serums be used in prevention and treatment?

702. Why doesn't a long lasting vaccine against common cold exist yet?

703. What are the types of antigenic agents that may constitute vaccines?

704. Why are vaccines made of the own disease agent or of fragments of it?

705. What are natural active immunization and artificial active immunization?

706. What is the difference between homologous and heterologous immunoglobulins?

707. How are antivenoms produced? Why are antivenoms an example of passive immunization?

708. Why is maternal milk important for the immune protection of the baby?

709. What are passive and active immunization? According to the duration of the protection how do these types of immunization differ?

710. What are the antigen- presenting cells of the immune system?

711. How does the cellular immune response take place?

712. How different are the actions of antibodies against bacteria and against virus? Why is the cellular immune response activated in case of chronic viral infection?

713. How can the immune memory lead to the efficacy of vaccines and also produce allergies?

714. How can an organism that once underwent contact with an antigen be immunized against future infections by the same agent?

715. How do antibodies work to neutralize antigens?

716. What are immunoglobulins?

717. What are the cells responsible for the production of antibodies?

718. What is an antigen?

719. What is the difference between humoral specific immune response and cellular specific immune response?

720. What is the defense mechanism that begins to work when inflammation fails to stop an infection?

721. Of which type of defense cell do viral infections stimulate the multiplication?

722. Of which type of defense cell do worm infections stimulate the multiplication?

723. Which type of defense cell do bacteria attract and cause to multiply during the inflammation process? What is the name given to the waste material produced by the inflammation triggered by bacterial infection?

724. What is the association between inflammation and fever?

725. What is pus?

726. How does the inflammation mechanism work?

727. What are the two groups of defense mechanisms of the body against foreign or harmful agents? What is the difference between them?

728. What is inflammation?

729. What is the function of the immune system?

730. Why are glucorticoids used in transplant patients?

731. What is the endocrine function of the placenta?

732. What is the endocrine function of the placenta?

733. What are the hormones produced by the testicles and the ovaries?

734. What are the hormones secreted by the adrenal cortex? What are their respective functions?

735. What are the hormones secreted by the adrenal medulla? What are their respective functions?

736. Where are the adrenal glands located? How many are they and what are their portions?

737. How can bacteria produce human insulin on an industrial scale? What are the other forms of insulin made available by the pharmaceutical industry?

738. What are the main treatments of diabetes mellitus?

739. In ancient Greece the father of Medicine, Hypocrates, described a method of diagnosing diabetes mellitus by tasting the patient's urine. What is the physiological explanation for this archaic method?

740. Why do diabetic patients often undergo dietary sugar restriction? What are the main complications of diabetes mellitus?

741. What is the difference between type I diabetes mellitus and type II diabetes mellitus?

742. What are the three main signs of diabetes?

743. What is diabetes mellitus?

744. What are the effects of somatostatin for the pancreatic hormonal secretion?

745. What is the importance of the glucose blood level for human health?

746. What are the target organs upon which insulin and glucagon act?

747. What are the functions of insulin and glucagon for the blood glucose control?

748. What are the pancreatic tissues involved respectively in the exocrine and endocrine secretions? What are their respective hormones and enzymes?

749. What is a mixed gland? Why is the pancreas considered a mixed gland?

750. What is the relation between secretion of parathormone and the calcium blood level?

751. What are the parathyroids? Where are they located and what are the hormones secreted by these glands?

752. What is a mixed gland? Why is the pancreas considered a mixed gland?

753. What is the physiological cause of the syndrome known as cretinism?

754. What is the relation between secretion of parathormone and the calcium blood level?

755. What are some signs and symptoms found in patients with hypothyroidism?

756. What are some signs and symptoms found in patients with hyperthyroidism?

757. What is a goiter? What is endemic goiter? How is this problem socially solved?

758. What happens to the TSH (thyroid-stimulating hormone) blood level in hypothyroidism? Why is there enlargement of the thyroid in the endemic goiter disease?

759. Why is the dietary obtainment of iodine so important for thyroid functioning?

760. What are the hormones secreted by the thyroid gland? What are their functions?

761. Why does the urinary volume increase when alcoholic beverages are ingested?

762. What is the difference between diabetes mellitus and diabetes insipidus? What are the characteristic signs of diabetes insipidus?

763. Where in the body is the thyroid gland located?

764. Which are the target organs and target tissues of the neurohypophysis?

765. What are the hormones secreted by the neurohypophysis? What are their respective functions?

766. What are the target tissues and target organs of each adenohypophyseal hormone?

767. What are some diseases caused by abnormal GH secretion by the hypophysis?

768. What is the relation between the thyroid and the hypophysis?

769. What are the hormones secreted by the adenohypophysis? What are their respective functions?

770. What is the relation between the hypothalamus and the hypophysis?

771. What are the main divisions of the hypophysis? What are their functions?

772. What is the osseous cavity where the pituitary gland is located?

773. Are hormones only proteins?

774. What is the pineal gland?

775. How does the circulatory system participate in the functioning of the endocrine system?

776. What are the main endocrine glands of the human body?

777. What are hormones?

778. What is the histological nature of the glands? How are they formed?

779. What is the constitution of the endocrine system?

780. Why is the endocrine system considered one of the integrative systems of the body? What is the other physiological system that also has this function?

781. What is the difference between the endocrine gland and the exocrine gland?

782. Why is there a sense of pressure change inside the ear when someone goes down a mountain?

783. What is the vestibular system? How does it operate?

784. What are the elements that constitute the internal ear? What are the functions of those structures?

785. How is the sound vibration captured by the tympanum transmitted through the ossicular chain of the middle ear?

786. What are the structures that form the external ear? What is its function?

787. What is the tympanum? In which part of the ear is it located and what is its function?

788. What are the main parts of the human ear?

789. What are the structures that participate in the human auditory sensitivity?

790. What are the elements that form the middle ear? What are the names of the three middle ear ossicles that participate in the phonosensitivity?

791. How can the visual deficiencies known as myopia and hypermetropia be optically explained?

792. What are presbyopia and astigmatism?

793. What are the near point and the far point of the vision?

794. Since the visual images are projected in an inverted manner on the retina why don't we see things upside down?

795. What is visual accommodation?

796. Which is the part of the human visual system where the receptors that sense light, i.e., the photoreceptor cells, are located? How do those cells work?

797. What type of structure is the crystalline lens? What is its function?

798. What is the function of the iris and of the pupil?

799. What are the main structures of the human eye?

800. What are the structures that compose the human vision apparatus?

801. How does photosensitivity in cnidarians, annelids and worms differ from insects, cephalopods and vertebrates?

802. What is vision? Why is vision important for life on earth?

803. According to the stimuli they collect how are the sensory receptors classified?

804. What are sensory receptors?

805. How does the nervous system get information about the external environment, the organs and the tissues?

806. What is the neuromuscular synapse?

807. Since neurotransmitters are not consumed in the synaptic process, what are the mechanisms to reduce their concentrations in the synaptic cleft after they have been used?

808. Fluoxetine is an antidepressant drug that presents an action mechanism related to the synaptic transmission. What is that mechanism?

809. What are some important neurotransmitters?

810. How does synaptic transmission between neurons take place?

811. What is the structure through which the neural impulse is transmitted from one cell to another? What are its parts?

812. What is the mechanism by which the neural impulse is transmitted along the axon?

813. In chemical terms how is the neuronal repolarization achieved?

814. How different are the concepts of action potential, resting potential and excitation threshold concerning neurons?

815. What is the excitation threshold of a neuron? How does this threshold relate to the “all-or-nothing” rule of the neural transmission?

816. How does the depolarization of the neuronal membrane start?

817. How is the depolarization of the neuronal plasma membrane generated? How does the cell return to its original rest?

818. How do the sodium and potassium ions maintain the resting potential of the neuron?

819. Which is the normal sign of the electric charge between the two sides of the neuron plasma membrane? What is the potential difference (voltage) generated between these two sides? What is that voltage called?

820. What are the two main ions that participate in the electrical impulse transmission in neurons?

821. What is the nature of the stimulus received and transmitted by the neurons?

822. What are the protective structures of the central nervous system present in vertebrates?

823. What are some main differences of the vertebrate nervous systems comparing to invertebrates?

824. Using examples of invertebrate nervous systems how can the process of evolutionary cephalization be described?

825. What is the antagonism between the sympathetic and the parasympathetic neural actions?

826. What are the two divisions of the autonomic nervous system?

827. What are the functional divisions of the nervous system?

828. Concerning volition of the individual how can the reactions of the nervous system be classified?

829. How does poliomyelitis affect the neural transmission in the spinal cord?

830. How is it explained that a person with the spinal cord sectioned at the cervical level is still able to perform the patellar reflex?

831. Is the neural impulse generated by the stimulus that triggers the arch reflex restricted within the neurons of this circuit?

832. What are the respective constituents of the gray matter and of the white matter of the spinal cord?

833. How is it explained that a person with the spinal cord sectioned at the cervical level is still able to perform the patellar reflex?

834. Which are the types of neurons that participate in the spinal arch reflex? Where are their cell bodies situated?

835. Is the neural impulse generated by the stimulus that triggers the arch reflex restricted within the neurons of this circuit?

836. What is meant by the arch reflex?

837. How is it structurally explained that the motor activity of the left side of the body is controlled by the right cerebral hemisphere and the motor activity of the right side of the body is controlled by the left cerebral hemisphere?

838. Which are the brain regions associated with memory?

839. What is the spinal cord? Of which elements is the spinal cord constituted?

840. Which is the brain region that receives conscious sensory information? Which is the brain region that triggers the voluntary motor activity?

841. Which is the brain region responsible for the regulation of breathing and blood pressure?

842. Why is the cerebellum more developed in mammals that jump or fly?

843. Which is the brain region responsible for the coordination and equilibrium of the body?

844. What are meninges and cerebrospinal fluid?

845. How is the cerebrum anatomically divided?

846. What are some diseases characterized by progressive loss of the axonal myelin sheath?

847. What is the difference between brain and cerebrum? What are the main parts of these structures?

848. What are the cells that produce the myelin sheath? Of which substance is the myelin sheath formed?

849. What are ganglia?

850. What are nerves?

851. What is the function of the myelin sheath? Do all axons present a myelin sheath?

852. What is meant by the peripheral nervous system (PNS)?

853. According to the function of the transmitted neural impulse which are the types of neurons? How different are the concepts of afference and efference of the neural impulse transmission?

854. What is an example of a situation in which the neuron cell body is located in a part of the body and its axonal terminal portion is in another distant part of the body? Why does this happen?

855. What are synapses?

856. What is the name of the terminal portion of the axon?

857. What are the three main parts into which a neuron can be divided? What are their respective functions?

858. Which are the structures that are part of the nervous system?

859. What are the functional differences between neurons and glial cells?

860. What are the physiological systems known as integrative systems? Why is this designation justified?

861. Which are the main cells of the nervous system?

862. To increase the strength of the muscle work is the muscle contraction intensely increased?

863. What is the difference between spatial summation and temporal summation of muscle fibers? What is tetany?

864. What is the neurotransmitter of the neuromuscular junction? How does the nervous system trigger muscle contraction?

865. How does phosphocreatine act in the muscle contraction and relaxation?

866. What is myoglobin? What is the function of this molecule in the muscle tissue?

867. What happens when the oxygen supply is insufficient to maintain aerobic cellular respiration during muscle exercise?

868. How do calcium ions participate in muscle contraction? Why do both muscle contraction and muscle relaxation spend energy?

869. What are the main proteins that constitute the sarcomere? What is the function of those molecules in the muscle cells?

870. What are the positions of actin and myosin molecules in the sarcomere before and during the muscle contraction?

871. What are sarcomeres?

872. How is the striped pattern of the striated muscle cells formed?

873. Which is the type of muscle tissue that helps to push the food down through the esophagus?

874. Which is the type of muscle tissue that moves the bones?

875. What are the types of muscle tissues? What are the morphological features that differentiate those types?

876. Which is the type of muscle tissue that performs the peristaltic movements of the intestines?

877. Which is the type of muscle tissue that contracts and relaxes the heart chambers?

878. What are the flat bones and the long bones?

879. What are the functions of the osseous tissue?

880. What is the bone matrix? What are its main components?

881. What are the three main cell types that form the osseous tissue? What are their functions?

882. What are the Haversian canals and the Volkmann’s canals of the bones? Is the osseous tissue vascularized?

883. What are some functions of the cartilages in the human body?

884. Which type of tissue are the cartilaginous and the osseous tissue?

885. What is the constitution of the cartilaginous matrix?

886. What are the functions of the musculoskeletal system?

887. What are the cells that form the cartilaginous tissue?

888. Which are the organs that are part of the musculoskeletal system?

889. What are melanocytes?

890. Which are the glands present in the epidermis of mammals, birds and reptiles?

891. How different is the fish epidermis from the amphibian epidermis?

892. What is the function of keratin in the epidermis?

893. How different is the simple squamous epithelium from the stratified squamous epithelium? Where can these epithelia be found in the human body?

894. How different is the simple cuboidal epithelium from the columnar epithelium? Where can these epithelia be found in the human body?

895. How are the epithelial tissues classified?

896. Is the epithelium vascularized? How do nutrients and oxygen reach the epithelium? Why is this feature an important evolutionary acquisition?

897. What are the specialized structures that help the adhesion between cells?

898. Besides the skin what are the other coverings of the body?

899. What is the typical feature of the epithelia? How different is it from the connective tissue?

900. What are the tissues that form the skin in vertebrates?

901. What are some functions of the epithelium?

902. What is the function of the skin in humans?

903. What is hemodialysis?

904. How does aldosterone act and where is it produced?

905. Why does the ingestion of alcohol increase diuresis?

906. What is an evolutionary explanatory hypothesis for the secretion by the heart of a hormone that regulates the renal function? Which is that hormone?

907. Why does the ingestion of alcohol increase diuresis?

908. What is the function of the antidiuretic hormone? Where is it made and which are the stimuli that increase or reduce its secretion?

909. Which are the three hormones that participate in the regulation of the renal function?

910. How do kidneys participate in the blood volume control? How is the blood volume of the body related to the arterial pressure?

911. How do kidneys participate in the regulation of the acid-basic equilibrium of the body? How are alkalosis and acidosis respectively corrected by the kidneys?

912. In which nephron portion does the regulation of acidity and alkalinity of the plasma occur?

913. What is tubular secretion? What are some examples of substances secreted through the renal tubules?

914. Why do cells of the nephron tubules present a great amount of mitochondria?

915. Where does most of the water resorbed after glomerular filtration go? What are the other substances resorbed by the nephron tubules?

916. What is proteinuria? Why is proteinuria a sign of glomerular renal injury?

917. What is the main transformation presented by the glomerular filtrate in comparison to the blood?

918. What are the three main renal processes that combined produce urine?

919. What is the functional unity of the kidneys?

920. Which are the vessels that drain filtered blood from the kidneys?

921. What is the main nitrogen waste of humans?

922. What are the vessels that carry blood to the kidneys? Is this blood arterial or venous?

923. How do embryos of placental mammals excrete nitrogen wastes?

924. Which are the organs of the excretory system?

925. Why is the uricotelic excretion essential for avian and reptile embryos?

926. How is urea formed in the human body?

927. What is the nitrogen waste in amphibian larvae and in the adult animal?

928. Comparing toxicity and the need for dilution in water how different are the ureotelic and the uricotelic excretions? What are some examples of animals that present these respective types of excretion?

929. Why are most ammoniotelic beings aquatic animals?

930. Why after the passage of animals from the aquatic to the terrestrial habitat does the abandonment of the ammoniotelic excretion occur?

931. What are the three main types of nitrogen wastes excreted by living beings?

932. What are nitrogen wastes?

933. What is excretion?

934. How is heart contraction triggered?

935. Concerning the mixture of arterial with venous blood what is the difference between the human fetal circulation and the adult circulation?

936. What is the difference between the amphibian heart and the reptile heart?

937. How many chambers do the bird heart and the mammalian heart have? Concerning temperature maintenance what is the advantage of the double and complete circulation of these animals?

938. What is the difference between the amphibian heart and the reptile heart?

939. Why can the amphibian circulation be classified as double and incomplete?

940. How many heart chambers does the amphibian heart have?

941. Why is the fish circulation classified as a simple and complete circulation?

942. What is the difference between double closed circulation and simple closed circulation?

943. Does the fish heart pump venous or arterial blood?

944. How is carbon dioxide released by cellular respiration transported from the tissues to be eliminated through the lungs?

945. How many chambers does the fish heart have?

946. What is the stage of cellular respiration during which carbon dioxide is liberated?

947. Why is carbon monoxide toxic for humans?

948. In high altitudes is it necessary for the blood to have more or less hemoglobin?

949. What is the substance that stimulates the production of red blood cells? Which is the organ that secretes it? Under what conditions does this secretion increase?

950. What is hemoglobin F? Why does the fetus need a different hemoglobin?

951. Which are the two main metabolic gases transported by the blood?

952. How different are oxyhemoglobin and hemoglobin? Where is it expected to find a higher concentration of oxyhemoglobin, in peripheral tissues or in the lungs?

953. Of which type of tissue is the heart made? How is this tissue oxygenated and nutrified?

954. How do respiratory pigments act?

955. What is the stage of the cardiac cycle during which the ventricles are filled?

956. Is the ventricle lumen larger during systole or during diastole?

957. To which heart chamber does the blood go after leaving the left atrium? What is the valve that separates these compartments?

958. What is the valve that separates the aorta from the heart? What is the importance of that valve?

959. What and how many are the pulmonary veins?

960. What is the function of the left ventricle? Where does the blood go after leaving the left ventricle?

961. Do the arteries that carry blood from the heart to the lungs contain arterial or venous blood? What happens to the blood when it passes through the lungs?

962. What is the valve that separates the right ventricle from the pulmonary artery? Why is that valve important?

963. Which is the first (human) heart chamber into which blood enters? Where does the blood go after passing that chamber? What is the name of the valve that separates the compartments? Why is that valve necessary?

964. What is the function of the right ventricle? To where does the right ventricle pump the venous blood?

965. What is vena cava? Which type of blood circulates within the vena cava?

966. Concerning the thickness of their walls how different are the heart chambers?

967. Which are the heart chambers respectively where the entrance and the exit of blood occur?

968. Why in inflammatory and infectious conditions may clinical signs related to the lymphatic system occur?

969. What is the lymphatic system?

970. What are varices? Why are they more common in the inferior limbs?

971. What are the valves of the venous system? What is their function?

972. Are the arteries or the veins constituted of more muscle tissue? How different are the walls of these two types of blood vessels?

973. How do the muscles of the legs and of the feet contribute to the venous return?

974. What is the part of the vascular system that performs exchange of gases and other substances with the tissues?

975. What are arterial vessels, arteries and arterioles?

976. What is the difference between systole and diastole

977. What are venous vessels, veins and venules?

978. How does the heart impel the blood?

979. What is the difference between octopuses and mussels regarding their circulatory systems? How does that difference influence the mobility of these animals?

980. What are the typical components of a closed circulatory system?

981. Why, even though they have an open circulatory system, can flying insects like flies beat their wings with great speed?

982. What are the advantages of the closed circulatory system over the open circulatory system?

983. What is the alternative means for transport of substances in animals without a circulatory system? Why is blood important for larger animals?

984. What is a closed circulatory system?

985. What is an open circulatory system?

986. Do all animals have a circulatory system?

987. What are the two types of circulatory systems?

988. What is circulation?

989. Where are the chemoreceptors that detect the acidity of the blood and trigger the respiratory compensation located?

990. What is the difference between respiratory acidosis and metabolic acidosis and what is the difference between respiratory alkalosis and metabolic alkalosis?

991. How does the breathing process correct alkalosis?

992. How does the breathing process correct acidosis?

993. How does the pulmonary ventilation affect the carbon dioxide concentration in blood? What happens to the carbon dioxide concentration and to the blood pH when the respiratory frequency is either lowered or increased?

994. What are acidosis and alkalosis?

995. What are the consequences of shifting the chemical equilibrium of the formation of bicarbonate from carbon dioxide and water towards the consumption of products of the reverse reaction?

996. What is the structure of the central nervous system that regulates pulmonary respiration?

997. What are the consequences of shifting the chemical equilibrium of the formation of bicarbonate from carbon dioxide and water towards the increase of product (bicarbonate) formation?

998. What is the physical process through which gas exchange is accomplished in the pulmonary alveoli?

999. What is the chemical equation of the formation of bicarbonate from carbon dioxide and water? What is the enzyme that catalyzes this reaction?

1000. What is the gas exchange unit of the mammalian lungs?

1001. What are the blood vessels that carry venous blood to the heart? What is the blood vessel that collects arterial blood from the heart?

1002. How are inhalation and expiration carried out?

1003. What is hematosis? In humans where does hematosis occur?

1004. Which are the respiratory muscles in mammals?

1005. What is the difference between arterial and venous blood?

1006. How does the body defend itself from microorganisms and other harmful substances that enter the airway during the breathing process?

1007. What are the organs that form the human respiratory system?

1008. What is the anatomical reason for the left bronchus to be more elevated than the right bronchus? Why in most cases of aspiration of foreign material by children is the object found in the right bronchus?

1009. What are respiratory pigments? What are some respiratory pigments and in which animal groups can each of them be found?

1010. What are the three types of respiration in which the circulatory system transports gases?

1011. What is the difference between gills and lungs?

1012. What are branchiae? What are examples of animals that “breath” through branchiae?

1013. Besides vertebrates two invertebrate phyla contain species that make pulmonary respiration. Which are these phyla?

1014. Which animals make cutaneous respiration?

1015. What is the difference between respiration by diffusion and cutaneous respiration? Does blood participate in cutaneous respiration?

1016. Which animals make tracheal respiration? Is there a blood-like fluid that participates in this process?

1017. Beings from four phyla of the animal kingdom “breath” (do gas exchange) by diffusion. Which are those phyla? How is this type of respiration associated to features present in those animals?

1018. Oxygen comes from the environment and carbon dioxide in the end returns to the environment. How do small animals solve the problem of taking away and bringing these molecules from/to their cells? Why isn't that solution possible for larger animals?

1019. What is the chemical equation of the aerobic cellular respiration?

1020. What are the different types of gas exchange that occur in animals?

1021. Considering the chemical equation of the aerobic cellular respiration which molecules does the cell need and which molecules does it liberate in the process?

1022. What is the difference between respiration meaning gas exchange and cellular respiration?

1023. Cows swallow their food once and then this food goes back to the mouth to be chewed again. How can this phenomenon be explained?

1024. What is meant by “mutualist exploration of cellulose digestion”, a phenomenon that occurs in some mammals and insects?

1025. Compared to mammals do birds absorb more or less water in their digestive system? Why is this phenomenon an adaptation to flight?

1026. What are the special structures of the avian digestive tube and their respective functions?

1027. Where is it produced and what is the function of enterogastrone in the digestive process?

1028. How is it produced and what is the function of cholecystokin in the digestive process?

1029. Where is it produced and what is the function of secretin in the digestive process?

1030. How is it produced and what is the function of gastrin in the digestive process?

1031. The releasing of digestive secretions is controlled by hormones. What are the hormones that participate in this regulation?

1032. What are the main functions of the bacterial flora within the human gut?

1033. Why does the ingestion of vegetable fibers improve the bowel habit in people that suffer from hard stools?

1034. What are the so-called “good” and “bad” cholesterol?

1035. What is the special route that lipids follow during digestion? What are chylomicrons?

1036. From the intestinal lumen through to the tissues - what is the route of nutrients after digestion?

1037. In which part of the digestive tube is water is chiefly absorbed? What about the mineral ions and vitamins?

1038. After digestion the next step is absorption done by cells of the mucous membrane of the intestine. For this task a large absorption surface is an advantage. How is it possible in the small internal space of the body of a pluricellular organism to present a large intestinal surface?

1039. Why do protease- supplying cells of the stomach and of the pancreas make only precursors of the active proteolytic enzymes?

1040. What are the five human digestive secretions? Which of them is the only pne that does not contain digestive enzymes?

1041. Coming from the acid pH of the stomach which pH level does the chyme find when it enters the duodenum? Why is it necessary to maintain that pH level in the small intestine? What are the organs responsible for that pH level and how is it kept?

1042. Besides the pancreatic juice in the intestine there is the releasing of the enteric juice that contains digestive enzymes too. What are these enzymes and which type of molecule do each of these enzymes break?

1043. How does the pancreatic juice help the digestion of lipids? What is the involved enzyme?

1044. How does the pancreatic juice resume the digestion of carbohydrates? What is the involved enzyme?

1045. How does the pancreatic juice participate in the digestion of proteins? What are the involved enzymes?

1046. Besides the liver which is the other adnexal gland of the digestive system that releases substances in the duodenum participating in extracellular digestion?

1047. What are the digestive functions of the liver?

1048. What is the adnexal organ of the digestive system in which bile is stored? How does this organ react to the ingestion of fat rich food?

1049. What is the substance produced in the liver that acts in the small intestine during digestion? How does that substance act in the digestive process?

1050. By generally dividing food into carbohydrates, fats and proteins and considering the digestive process until the pylorus (exit of stomach), which of these mentioned types of food have already undergone chemical digestion?

1051. Which are the three parts of the small intestine?

1052. What name does the food bolus that passes from the stomach to the duodenum get?

1053. What is the digestive enzyme that acts within the stomach? Which type of food does it digest? What are the cells that produce that enzyme?

1054. How is the gastric mucosa protected from the acid pH of the stomach?

1055. Besides being fundamental for the activation of the main gastric digestive enzyme how does HCl also directly participate in digestion?

1056. What is the pH inside the stomach? Why is there a need to keep that pH level? How is it maintained? Which are the cells that produce that pH?

1057. What is the valve that separates the duodenum from the stomach called? What is its function?

1058. What is the valve that separates the stomach from the esophagus called? What is its function?

1059. What is the route of the ingested food from swallowing until the duodenum?

1060. Is the esophagus a muscular organ? Why even in a patient lying totally flat on a hospital bed can the swallowed food reach the stomach?

1061. Why doesn't the food enter the trachea instead of going to the esophagus?

1062. What is the salivary digestive enzyme? Which type of food does it digest and into which smaller molecules does it transform the food?

1063. What is the approximate pH of the salivary secretion? Is it an acid or basic fluid? What are the main functions of saliva?

1064. What is the location of the salivary glands in humans?

1065. From the lumen to the external surface what are the tissues that form the digestive tube wall?

1066. What are peristaltic movements? What is their role in human digestion?

1067. Which organs of the body are part of the human digestive system?

1068. Which type of chemical reaction is the breaking of macromolecules into smaller ones that occurs in digestion? What are the enzymes that participate in this process called?

1069. What is mechanical digestion? In molluscs, arthropods, earthworms, birds and vertebrates, in general, which organs respectively participate in this type of digestion?

1070. Concerning extracellular digestion what is meant by chemical digestion?

1071. What are some evolutionary advantages of animals with complete digestive tube?

1072. What is the difference between a complete digestive system and an incomplete digestive system? How are these types of digestive tubes associated or not to extracellular digestion?

1073. How is extracellular digestion related to cellular and tissue specialization?

1074. How different are intracellular and extracellular digestion? What is the evolutionary advantage of extracellular digestion?

1075. How is extracellular digestion related to cellular and tissue specialization?

1076. What is digestion?

1077. What is the importance of iron in diet? What is the disease caused by iron deficiency?

1078. What is the disease caused by dietary iodine deficiency?

1079. What are some examples of mineral salts from the diet that act as coenzymes?

1080. What are the functions of biotin and pantothenic acid for the body? How are these vitamins obtained?

1081. What are the main cellular functions of potassium?

1082. Why are some types of hemorrhagic diseases caused by genetic or acquired deficiency of the vitamin K metabolism?

1083. What are the main mineral salts responsible for the cellular osmotic regulation?

1084. What is the function of vitamin E? In which foods can it be found?

1085. What is the disease caused by vitamin D deficiency? Which tissue does it affect?

1086. What is the association between vitamin D and sunrays?

1087. Why isn't the cooking of vitamin C-containing foods appropriate for vitamin C supply?

1088. How does vitamin C act in the body? What is the harm caused by insufficiency of vitamin C? Why was this deficiency also known as “sailors' disease”?

1089. What are the vitamins which make up the B complex? Which problems does the lack of these vitamins cause?

1090. What is folic acid? Why is the anemia caused by deficiency of folic acid known as megaloblastic anemia?

1091. What are the main harms caused by vitamin A deficiency? How does this vitamin act in the physiology of vision?

1092. What is the difference between water-soluble and fat-soluble vitamins? Why can fat-soluble vitamins cause harm when ingested in excess?

1093. What are vitamins? What are the main vitamins needed by humans?

1094. According to their functions how can nutrients be classified?

1095. What is the difference between macro and micronutrients?

1096. What is a nutrient?

1097. What is an example of positive feedback of the homeostatic regulation?

1098. What is an example of negative feeback of the homeostatic regulation?

1099. How do antagonistic mechanisms manage homeostatic regulation?

1100. What is homeostasis? What are the sensors, controllers and effectors of homeostasis?

1101. What is the difference between anabolism and catabolism?

1102. What is metabolism?

1103. Streptokinase is a substance used in the treatment of acute myocardial infarction. How does this substance act?

1104. What is dicoumarol? How does this substance act in the clotting process and what are some examples of its toxicity?

1105. What are anticoagulants? What are the practical applications of anticoagulants, like heparin, in Medicine?

1106. What is the epidemiological association between hemophilia and HIV infection?

1107. What is the organ where most of the clotting factors are produced? What is the role of vitamin K in the blood coagulation?

1108. How is hemophilia treated? Why is hemophilia rare in females?

1109. What are clotting factors?

1110. What is factor VIII? What is the genetic disease in which this factor is absent?

1111. How can the blood coagulation (clotting) process be described?

1112. How does the organism understand that a clotting process must begin?

1113. How are platelets formed? What is the function of platelets? What consequences does the clinical condition known as thrombocytopenia yield?

1114. What are the mechanisms of hemorrhage contention called?

1115. What is the generic function of leukocytes? What are leukocytosis and leukopenia?

1116. What are the types of leukocytes and how are they classified into granulocytes and agranulocytes?

1117. What is the difference between white and red blood cells? What are leukocytes?

1118. What is anemia? What are the four main types of anemia?

1119. What are the functions of the spleen? Why is a total splenectomy (surgical removal of the spleen) compatible with life?

1120. What is the molecular composition of hemoglobin? Does the functionality of hemoglobin as a protein depend upon its tertiary or upon its quaternary structure?

1121. What is the name of the molecule that transports oxygen in red blood cells?

1122. On average what is the life duration of the red blood cells? Where are they destroyed? What is the destination of the heme groups after the destruction of hemoglobin molecules?

1123. What are the other names by which erythrocytes are known? What is the function of these cells?

1124. What are blood stem cells?

1125. In which bones can bone marrow chiefly be found? Is the bone marrow made of osseous tissue?

1126. Where does hematopoiesis occur?

1127. What is hematopoiesis?

1128. What are the constituent elements of the blood?

1129. What are the main functions of the blood?

1130. What are diseases of the connective tissue? What are some of them?

1131. What are the reticular fibers of the connective tissue and where can they be found?

1132. Of which substance do elastic fibers of the connective tissue are made? What are some functions of these fibers?

1133. What are the main cells of the connective tissue proper? What is the name given to the intercellular material that surround these cells?

1134. What is the function of the collagen fibers of the connective tissue?

1135. What is connective tissue proper?

1136. What are the three types of protein fibers of the connective tissue proper?

1137. What are the general functions of the connective tissues?

1138. Are the cells of the connective tissue far or near to the others?

1139. Of which type of tissue are cartilages and bones made?

1140. What is the typical biological function of the connective tissues? How is this function associated to the main features of its cells?

1141. What are muscle tissues? How is the function of this tissue related to the typical characteristics of its cells?

1142. Of which cells is the nervous tissue constituted? How is the generic function of this tissue related to the characteristics of the main cell type that forms it?

1143. What are epithelial tissues? What are their general function and how is that function associated to the features of the tissue?

1144. What are the main types of animal tissue?

1145. From the zygote, pluricellular organisms are formed by serial mitosis. Would this formation be possible if each cell made by mitosis had an identical life in relation to its antecedent cells? How did evolution solve that problem?

1146. What is the logical order in which the concepts of atoms, molecules, cells... up to biosphere are associated?

1147. Mammal identity card. How are mammals characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?

1148. Are the limbs modified into wings of bats and the wings of birds examples of evolutionary analogy or homology? What about whale fins compared to fish fins?

1149. Are there aquatic and flying mammals?

1150. Is the mammalian embryonic development direct or indirect?

1151. Is fecundation in mammals internal or external?

1152. How do placental mammals reproduce?

1153. What is the type of nitrogen waste that mammals eliminate?

1154. How is circulation characterized in mammals?

1155. How is gas exchange done in mammals?

1156. What are the main orders of placental mammals? What are some representative species and distinguishing features of each of those orders?

1157. Do all mammals have a placenta?

1158. What are the three main groups into which mammals are divided?

1159. What are the typical features of mammals?

1160. Bird identity card. How are birds characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?

1161. Is the embryonic development in birds direct or indirect?

1162. What are zoonoses? What are some examples of zoonoses transmitted by birds?

1163. How different are reptiles and birds concerning the maintenance of body temperature? Are birds rare in polar regions?

1164. How do birds reproduce?

1165. What are the predominating chemical compounds respectively in eggshell, white and yolk?

1166. What similarities do birds and reptiles share regarding external coverage, reproduction and excretion?

1167. What are pneumatic bones?

1168. What is crystallization of a virus? What is the importance of this process?

1169. Which is the type of nitrogen waste birds produce? Why does this feature, besides being an adaptation to the terrestrial environment, also mean an adaptation to flight?

1170. What are flight adaptations present by birds?

1171. SARS is a disease that appeared in 2003 with epidemic features in the province of Guangdong, in east China. What type of agent causes SARS?

1172. How is the circulatory system of birds characterized?

1173. In which habitat do birds live?

1174. SARS is a disease that appeared in 2003 with epidemic features in the province of Guangdong, in east China. What type of agent causes SARS?

1175. How is the respiratory system of birds characterized?

1176. What are the main human diseases caused by virus?

1177. What are the main morphological features of birds?

1178. What is meant when it is said that a virus is in an inactive state?

1179. Class Reptilia identity card. How are they characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?

1180. What are bacteriophages?

1181. What is the basic structure of the HIV virus? What is the function of the glycoproteins of its envelope?

1182. What is an example of a hypothesis which may explain why there is not a big representation of the class Reptilia found in polar regions?

1183. What are retroviruses? How do they reproduce and what is the role of the enzyme reverse transcriptase?

1184. Do beings of the class Reptilia have direct or indirect development?

1185. What is the typical reproduction cycle of a DNA virus?

1186. Concerning the maintenance of body temperature how do beings of the class Reptilia classify?

1187. What is the genetic material of a virus? How does that material act in viral reproduction?

1188. How is reproduction done in beings of the class Reptilia?

1189. ]Why is it a strong evolutionary hypothesis that although viruses are the structurally simplest beings they were not the first living beings?

1190. Are there non-parasitic viruses?

1191. What is the basic structure of a virus?

1192. Compared to amphibians what are the two reproductive novelties of beings of the class Reptilia for the survival in dry environments?

1193. Are viruses cellular beings?

1194. How has the importance of the brain evolved from fishes to reptiles?

1195. What is cyclosporin? How are fungi related to this substance?

1196. What are the main human diseases caused by fungi?

1197. Which is the type of nitrogen waste eliminated by beings of the class Reptilia?

1198. What are mycorrhizas? How does each participant benefit in this ecological interaction?

1199. How is the circulatory system of reptiles characterized? What is the basic difference between the reptile and the amphibian heart?

1200. What is the utility of fungi for some industries?

1201. Fungi are classified in their own kingdom. Into which phyla is the fungi kingdom divided? Into which of those phyla are mushrooms classified?

1202. Do beings of the class Reptilia perform gas exchange in the same way amphibians do?

1203. What are examples of a carnivorous and a herbivorous reptile?

1204. Are there photosynthetic fungi? How do fungi nourish themselves?

1205. Compared to amphibians what is an example of evolutionary novelty present in beings of the class Reptilia against the loss of water through the skin?

1206. What are the main cellular features of fungi?

1207. Which is the vertebrate class that is considered the first entirely terrestrial?

1208. What is the phenomenon known as “red tide”? Which ambiental harms can it cause?

1209. Amphibian identity card. How are amphibians characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?

1210. What is the commercial importance of algae?

1211. Do algae reproduce sexually or asexually?

1212. What are the problems that vertebrates needed to solve to adapt to the terrestrial environment since they came from the aquatic habitat? How does evolution solved those problems?

1213. Why are euglenas involved in polemics related to their taxonomic classification?

1214. Why is the occurrence of eyelids in amphibians in comparison to their absence in fishes an adaptation to terrestrial life?

1215. What are the four groups of protozoans?

1216. Is fecundation in amphibians external or internal? In this aspect are amphibians evolutionarily proximal to fishes or to reptiles?

1217. Are protozoans presenting contractile, or pulsatile, vacuoles easily found in fresh or in salt water?

1218. How is excretion done in amphibians?

1219. How different is the amphibian heart from the fish heart?

1220. How is respiration performed by the larva of amphibians?

1221. How different are the respiration in fishes and the respiration in adult amphibians?

1222. Do amphibians have direct development?

1223. What are the amphibian features that make them dependent on water to survive?

1224. Which is the chordate class considered an evidence of the transition of the vertebrates from the aquatic to the dry land environment?

1225. How is digestion performed in protozoans?

1226. Fish identity card. How are fishes characterized according to examples of representing beings, basic morphology, skin, respiration, circulation, nitrogen waste, thermal control and types of reproduction?

1227. How do amoebae, paramecia and trichomonas respectively move?

1228. How different are fecundation in osteichthyes and in chondrichthyes?

1229. What are the lateral lines of fishes?

1230. What do protozoans “eat”? Do they move in search for food?

1231. What are the respective functions of the macronucleus and of the micronucleus in the paramecium?

1232. How is excretion done in fishes?

1233. Do protozoans have a cellular nucleus?

1234. How do fishes do gas exchange?

1235. Do fishes present an open or closed circulatory system? How many chambers does a fish heart have? How does blood flow throughout the fish body?

1236. How does the swim bladder of fishes work allowing fishes to control their depth under water?

1237. What is the basic morphology of a protozoan cell?

1238. What are the main features of fishes associated to the habitat where they live?

1239. How different are the swimming strategies in osteichthyes and in chondrichthyes? Why do sharks need to agitate their body to swim while bony fishes do not?

1240. What are the characteristics of protozoans that make them resemble animals?

1241. From which features do condrichthyes and osteichthyes get these names?

1242. Comparing to cyclostomes (primitive vertebrates) what are the main novelties presented by fishes?

1243. What are the two main classes into which fishes are divided?

1244. Which are the groups of living beings that form the protist kingdom?

1245. Chordate identity card. How are they characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1246. How does sexual reproduction occur in bacteria? How different are the modalities of bacterial sexual reproduction?

1247. Evolutionarily protochordates may be intermediate animals between invertebrates and vertebrates. Imagine a scientist is testing the hypothesis that vertebrates evolved from echinoderms. Having as research object a newly found protochordate species, what is an example of a discovery that would weaken the hypothesis? What is an example of a discovery that would strengthen it?

1248. How do bacteria reproduce?

1249. What are the six criteria used to build a complete evolutionary branch of vertebrates?

1250. Into which subphyla are the protochordates divided? What are some representatives of each protochordate subphylum?

1251. How do chordates reproduce?

1252. What is the group of the phylum Chordata that first colonized the terrestrial environment? From which habitat did they come?

1253. How can the tubular-dorsal nervous system in chordates be compared to the nervous pattern present in invertebrates?

1254. What is the destination of the branchial clefts in humans?

1255. Is the tubular-dorsal nervous system of chordates associated to radial or lateral symmetry? How does that explain the complexity level of the nervous system reached by the vertebrate evolutionary branch?

1256. What are the three structures shared by every chordate that characterize the group?

1257. What is the destination of the notochord in vertebrates and in protochordates?

1258. What are the two main subdivisions of the phylum Chordata?

1259. What are the classes into which the phylum Echinodermata is divided?

1260. Echinoderm identity card. How are echinoderms characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1261. Is there a larval stage in echinoderms?

1262. Do echinoderms present internal or external fecundation? Is there sex division among individuals?

1263. Do echinoderms have respiratory and circulatory systems?

1264. How are the symmetry and the nervous system characterized in echinoderms?

1265. What is the embryonic characteristic that evolutionarily makes echinoderms proximal to chordates?

1266. Do echinoderms have an excretory system? How is excretion done in these animals?

1267. Do sea urchins have teeth?

1268. What is the type of digestive system of echinoderms?

1269. What is the system that permits movement and fixation to echinoderms?

1270. What are the basic morphological features of echinoderms?

1271. Under which environments do echinoderms live?

1272. How can the endoskeleton of echinoderms be characterized in comparison to analogous structures present in vertebrates, arthropods and molluscs?

1273. How are natural and artificial pearls created?

1274. Mollusc identity card. How are molluscs characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1275. What are examples of the ecological and economic importance of molluscs?

1276. How is the nervous system of molluscs organized?

1277. What is the function of the feet in molluscs? How is the mollusc foot related to the name given to the classes of the phylum?

1278. Which other phylum of the animal kingdom present species with exoskeleton?

1279. Do octopus and squids have exoskeleton?

1280. What type of exoskeleton do some molluscs present?

1281. How is the excretory system of molluscs characterized?

1282. How is the large size of some cephalopods related to the type of circulatory system they present?

1283. Which type of circulatory system do molluscs have? How can it be compared to the respiratory system of annelids?

1284. How is the respiratory system in aquatic molluscs characterized? What adaptive respiratory structure do terrestrial molluscs present?

1285. What is the radula? What is the function of this organ?

1286. What is the type of digestive system in molluscs?

1287. How is the body of gastropods divided?

1288. Into which classes are mollusc divided? What are some representing beings of each class?

1289. Are mollusc metameric beings? Exclusively analyzing this feature could it be said that molluscs are evolutionarily proximal to nematodes or to annelids?

1290. What are the biological troubles that molluscs face due to their soft body?

1291. What is the morphological feature of molluscs after which the phylum is named?

1292. In which habitats do molluscs live?

1293. What are some representatives of the phylum Mollusca?

1294. Arthropod identity card. How are arthropods characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1295. What are some examples of beings of the phylum Arthropoda that present a high level of behavioral sophistication?

1296. Which arthropod class is the most diversified animal group of the planet? How can this evolutionary success be explained?

1297. How are the three main arthropod classes characterized according to the number of limbs?

1298. How are the three main arthropod classes characterized according to the body division?

1299. How are the three main arthropod classes characterized according to the presence of antennae?

1300. How are animals divided according to their type of digestive process?

1301. What is the typical shape of poriferans?

1302. How do sponges try to protect themselves against harm from the environment? Is that method efficient or rudimentary?

1303. What is the way of life of sponges?

1304. Most insects have wings. Which is the other animal phylum that contains creatures with analogous organs?

1305. How are the three main arthropod classes characterized according to the presence of wings?

1306. Is the stage when an insect larva is within a cocoon a stage of total biological inactivity?

1307. What are nymph and imago?

1308. How are the main classes of arthropods classified according to the presence of larval stage in their embryonic development?

1309. How is fecundation done in insects (external or internal)? Is there copulation between insects?

1310. What are the types of fecundation that occur in arthropods? What is the predominant type?

1311. What are the noteworthy features of the nervous system of arthropods?

1312. How is arthropod reproduction characterized?

1313. What are compound eyes?

1314. How are the excretory systems of the three main arthropod classes constituted?

1315. How is the respiratory system of insects (with its independence between circulation and respiration) related to the motor agility of some species of this arthropod class?

1316. What is the type of circulatory system present in arthropods? Do these animals have heart and respiratory pigments?

1317. In arthropods why isn't gas exchange done through cutaneous diffusion?

1318. What are respiratory pigments? What is the respiratory pigment present in some arthropods? Which is the analogous molecule in humans?

1319. Which organs or respiratory adaptations do aquatic and terrestrial arthropods respectively present?

1320. How can the features of the arthropod exoskeleton explain the terrestrial adaptation of some species of the phylum?

1321. How is the extracorporeal digestion associated to predation in arachnids?

1322. How does the presence of exoskeleton explain the general small size of arthropods?

1323. What is the type of digestive system present in beings of the phylum Arthropoda? Are these animals protostomes or deuterostomes?

1324. How do arthropods grow?

1325. What is the external rigid carapace of arthropods called? Of which substance is it made? Which type of organic molecule is that substance?

1326. What are the main morphological features of arthropods?

1327. Considering the presence of segmentation (metameres) in their body to which other already studied phylum are arthropods proximal?

1328. Concerning germ layers and the presence of coelom how are arthropods characterized?

1329. What are some examples of arthropods?

1330. Annelid Identity card. How are they characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1331. What is the name of the larval stage of polychaetes?

1332. Is the embryonic development in earthworms direct or indirect?

1333. Into which classes is the phylum Annelida divided?

1334. Concerning the occurrence of separated sexes how are the beings of the phylum Annelida classified?

1335. What is the ecological role of earthworms?

1336. What is the clitellum of earthtworms and where it is located?

1337. How is the nervous system characterized in beings of the phylum Annelida? How can one compare cephalization in annelids to cephalization in nematodes and platyhelminthes?

1338. How can the excretory system of annelids be described?

1339. How can the presence, localization and function of muscular tissue in beings of the phylum Annelida be explained?

1340. Is there a respiratory pigment in the annelid blood?

1341. What is the type of circulatory system present in annelids?

1342. How are the circulatory systems of animals classified?

1343. What is meant when it is said that beings of the phylum Annelida are vascular beings? From which other phyla of the animal kingdom does this feature differentiate them?

1344. How is the respiratory system of beings of the phylum Annelida characterized?

1345. The vascular lesions caused by leeches upon the blood vessels of their host cause blood naturally to coagulate. How does the leech solve this problem since it could be expected that the ingested blood would coagulate inside its body?

1346. Which are the characteristics and organs of the digestive system of earthworms related to the type of diet of these animals?

1347. How does digestion in beings of the phylum Annelida work and which type of digestive system do they have?

1348. What is the morphological characteristic that evolutionarily approximates the beings of the phylum Annelida to arthropods?

1349. What is the main evolutionary novelty presented by annelids?

1350. Which are the morphological features that differentiate the beings of the phylum Annelida from nematodes and platyhelminthes?

1351. What are some examples of annelids?

1352. Nematode identity card. How are nematodes characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1353. What are the main human diseases caused by roundworms?

1354. What is the type of reproduction that occurs in roundworms? What typical feature do nematode sperm cells have?

1355. How is the nervous system of nematodes organized? Where are the neural chords located in their body?

1356. How does the excretory system of nematodes work?

1357. Compared to platyhelminthes which physiological problem have the cylindrical body of nematodes brought? How was that problem solved?

1358. What is the main evolutionary innovation presented by nematodes? What is the advantage of that innovation?

1359. Are nematodes diploblastic or triploblastic animals?

1360. What are the morphological similarities and differences between nematodes and annelids?

1361. What is the typical morphological feature of nematodes that differentiates them from platyhelminthes?

1362. Are nematodes exclusively parasites?

1363. What are examples of nematodes?

1364. Platyhelminth identity card. How are platyhelminthes characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1365. What are the main human diseases caused by platyhelminthes?

1366. Into which classes are platyhelminthes divided? How are these classes characterized and what are some representative beings of each of them?

1367. What is direct development? Is there a larval stage in planarias?

1368. Is it possible for a hermaphrodite species to present cross-fecundation?

1369. Are flatworms monoecious or dioecious?

1370. How can asexual reproduction in planarias be described?

1371. What is the type of reproduction, sexual or asexual, that occurs in platyhelminthes?

1372. What is cephalization? How does lateral symmetry favor cephalization?

1373. Is the nervous system in platyhelminthes more or less sophisticated than in cnidarians? What are the main neural structures found in flatworms? How is this neural organization important for the diversity of biological niches explored by species of the phylum?

1374. What is an example of freshwater flatworm? Due to that habitat what is the physiological problem that these animals must solve?

1375. Poriferans and cnidarians do not have excretory systems. Do platyhelminthes have an excretory system?

1376. How many germ layers originate the body of platyhelminthes? In relation to this characteristic how are these animals classified?

1377. How is gas exchange done in flatworms?

1378. What is the main external morphological feature that differentiates platyhelminthes from other worms (nematodes)?

1379. How are nutrients distributed by the digestive system in planarias?

1380. What are the types of digestion and of digestive system of platyhelminthes?

1381. What are the best known representatives of the platyhelminth phylum?

1382. Cnidarian identity card. How are they characterized according to examples of representing beings, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1383. What are corals?

1384. What does radial symmetry means? What is the type of symmetry found in chordates? Which are other phyla of the animal kingdom that present species with radial symmetry?

1385. What are the main classes into which the phylum is divided? What are some examples of each and in which form (polyp or medusae) are they found?

1386. What is the name of the larva of corals and sea anemones? What is the biological importance of that larval stage?

1387. In the metagenesis of Aurelia and Obelia what is the form that produces gametes? What is the form that reproduces asexually?

1388. What is metagenesis? What are the other names of this process?

1389. What is the type of asexual reproduction that occurs in hydras?

1390. What are the types of reproduction presented by cnidarians?

1391. How is the nervous tissue distributed in cnidarians?

1392. What are cnidocytes? What is the name of the capsule inside the cnidocyte? What are the biological functions of this structure?

1393. What is the type of digestion that occurs in cnidarians?

1394. Why is the digestive system of these animals called incomplete?

1395. What are the two main morphological patterns of cnidarians? Concerning locomotion how do these forms differentiate from each other?

1396. Which are the germ layers present in cnidarians? Which tissues of the animal do they originate?

1397. Concerning tissue complexity how different are cnidarians from poriferans?

1398. What are some examples of cnidarians? In which environments can these animals be found?

1399. Sponge identity card. How are sponges characterized according to example of representing beings, basic morphology, type of symmetry, embryonic (germ) layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1400. Sponge identity card. How are sponges characterized according to example of representing beings, basic morphology, type of symmetry, embryonic (germ) layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

1401. What is the economic importance of sponges?

1402. How are gases exchanged in sponges?

1403. What is the evolutionary advantage of the occurrence of sperm cells and larval stage in the life cycle of sponges?

1404. How are animals divided according to their type of digestive process?

1405. Is reproduction in sponges sexual or asexual?

1406. Concerning digestion how are poriferans characterized?

1407. Do sponges have nervous, circulatory and excretory systems?

1408. How are gases exchanged in sponges?

1409. How are animals divided according to their type of digestive process?

1410. Concerning digestion how are poriferans characterized?

1411. What are the main cells of which poriferans are made?

1412. What is the typical shape of poriferans?

1413. How do sponges try to protect themselves against harm from the environment? Is that method efficient or rudimentary?

1414. What is the way of life of sponges?

1415. How does water move inside sponges? What is the function of the pores in these animals?

1416. What are poriferans?

1417. What is an evolutionary tree? Is there a precise evolutionary tree known by science that explains the emergence and origin of every type of living being?

1418. What are the five classes of vertebrates? To which of these do human beings belong?

1419. What are the differences between vertebrates and the other chordates?

1420. What are the two mains divisions of the chordate phylum?

1421. Which are the beings that form the kingdom Plantae? Are algae part of this kingdom?

1422. What are the two mains divisions of the chordate phylum?

1423. Which are the beings that form the kingdom Fungi?

1424. What are the nine phyla of the kingdom Animalia?

1425. Which are the beings that form the kingdom Protista?

1426. Which are the beings that constitute the kingdom Monera?

1427. Which are the beings that form the kingdom Animalia? What are the two big groups into which this kingdom is divided?

1428. According to cellular organization how are living beings divided into two groups?

1429. What are the five kingdoms into which living beings are divided? Which group of living being is out of this classification?

1430. What is meant by binomial nomenclature and what are its basic rules?

1431. Into which categories are living beings classified?

1432. What is the Biology field that studies the classification of living beings?

1433. How does the universality of the genetic code make the recombinant DNA technology possible?

1434. What is the concept of universality of the genetic code? What are the exceptions to this universality?

1435. Why can the genetic code be qualified as a “degenerate code”?

1436. If a fragment of nucleic acid has a nucleotide sequence TAC can one assert that it is a codon or an anticodon?

1437. If a tRNA anticodon is CAA what is its corresponding mRNA codon? For the genetic code which amino acid does this codon codify?

1438. An mRNA molecule codifies only one type of protein?

1439. How many of the same proteins are made at the same time by each ribosome in the translation of one mRNA molecule? How does consecutive protein production occur in translation?

1440. Why do ribosomes move along mRNA during translation?

1441. Why is the proximity between ribosomes and amino acids important for the protein formation? What is the enzyme that catalyzes that reaction?

1442. How are amino acids brought to the cellular site where translation takes place? What is an anticodon?

1443. What is the cellular structure to which mRNA molecules bind to start the protein synthesis?

1444. Since among the 64 codons of mRNA 61 codify amino acids that form polypeptide chains what are the functions of the three remaining codons?

1445. What is the name of an RNA sequence that codifies one amino acid?

1446. What are plasmids? What is the importance of plasmids for the recombinant DNA technology?

1447. Which are the intracellular organelles present in bacteria?

1448. What is the main constituent of the cell wall of bacteria?

1449. According to their morphology how are bacteria classified?

1450. What is meant when it is said that a bacteria is an obligate anaerobe?

1451. How are bacteria classified according to their need for oxygen?

1452. How are bacteria classified according to the production of organic material for the energetic metabolism?

1453. In which environments do bacteria live?

1454. What are some mechanisms by which pathogenic bacteria cause diseases? Why is this knowledge important?

1455. What are some industrial processes that use bacteria?

1456. What are the main ecological roles of bacteria?

1457. What are halophile, thermoacidophile and methanogen archaebacteria?

1458. Are bacteria the only prokaryotic beings?

1459. What are bacteria?

1460. How do nucleotides of mRNA chains encode information for the formation of the amino acids sequences of a protein?

1461. What is the difference between transcription and translation?

1462. After the fact that it is based on information from mRNA what is the process of protein synthesis called?

1463. Where in eukaryotic cells does mRNA synthesis occur? To where do these molecules migrate?

1464. Which are the more abundant ribosomes in secretory cells - the free cytoplasmic ribosomes or those associated with the rough endoplasmic reticulum?

1465. What are some examples of human cells that produce proteins for exportation? Which cytoplasmic organelle is expected to be well- developed and abundant in those cells?

1466. How is the finding of ribosomes inside mitochondria and chloroplasts explained?

1467. How different are the location of ribosomes in eukaryotic and in prokaryotic cells?

1468. Of what subunits are ribosomes are made?

1469. What is the role of messenger RNA and ribosomes for the protein synthesis?

1470. How are the concepts of DNA, gene, proteins and characteristics of living beings related?

1471. Which is the biological molecule that contains the genetic information that is transmitted hereditarily and controls the cellular functioning?

1472. What is the genetic code?

1473. Why can the consumption of molecular oxygen indicate the metabolic rate of aerobic organisms?

1474. What is the general equation of the aerobic respiration (also representing ADP and phosphate)?

1475. How many ATP molecules are made after the aerobic respiration and what is the net energetic gain of the process?

1476. What is anoxia?

1477. How does the poison cyanide act upon the aerobic respiration?

1478. Until the Krebs cycle, aerobic respiration can be described without mentioning oxygen, the chemical element after which the reaction gets its name. Where in the process does this chemical element take part? What is its importance?

1479. How in the respiratory chain do electrons from FADH2 and NADH2 passing through cytochromes liberate energy for the ATP synthesis? What is this ATP synthesis called?

1480. What are cytochromes?

1481. Where in mitochondria does the process called respiratory chain occur? Which are the products of the Krebs cycle used in that final phase of the aerobic respiration?

1482. How many carbon dioxide molecules are liberated after each cycle of the Krebs cycle? For a single glucose how many carbon dioxide molecules were already liberated by the aerobic respiration at that point?

1483. What are the final energetic products of each round of the Krebs cycle? Where is most part of the utile energy at the end of Krebs cycle found?

1484. Why is the Krebs cycle also called the final common pathway of the degradation of organic compounds?

1485. Why can it be said that each glucose molecule runs the Krebs cycle twice?

1486. What is the official name of pyruvic acid?

1487. What happens during aerobic respiration to the pyruvic acid molecules made by glycolysis? What is the sequence of reactions that then follows?

1488. What is NAD? What is the role of the NAD molecule in glycolysis?

1489. How many ATP molecules are made after glycolysis?

1490. Does glycolysis occur within the mitochondria?

1491. What is glycolysis? What are the products of this process?

1492. What are the three phases into which the cell respiration is divided?

1493. Of which main compounds is the mitochondrion structure made?

1494. Which is the cell organelle that is specialized in aerobic respiration?

1495. How many ATP molecules are produced for each glucose molecule used in fermentation? How many ATP molecules are produced for each glucose molecule used in aerobic respiration?

1496. How can the knowledge about fermentation explain the origin of muscle cramps and pains after intense physical exertion?

1497. To what substance is the acidic flavor of fermented milk due?

1498. Why in cake and bread manufacture are alcoholic fermenting organisms used and not lactic fermenting organisms?

1499. In general what are the reagents and products of fermentation?

1500. What are the two types of fermentation? What are their chemical equations?

1501. What is the difference between facultative anaerobic beings and obligate anaerobic beings?

1502. What is the difference between aerobic and anaerobic beings?

1503. Under which conditions do aerobic cells carry out fermentation?

1504. What are the types of cell respiration?

1505. What is the compound that is phosphorylated for ATP formation? What is the resulting compound when ATP liberates energy?

1506. How do cells obtain energy for their functioning?

1507. Why do some trees lose their green color in the autumn?

1508. Why is the carbon dioxide concentration a limiting factor of the photosynthesis process? When the carbon dioxide concentration is increased indefinitely is photosynthesis also increased indefinitely?

1509. What is the compensation point? What is the implication of the compensation point for the plant growth?

1510. Photosynthesis rate varies according to the photic energy intensity. Does the same occur in aerobic respiration? What happens to the glucose balance as a result of these variations?

1511. What are the three main limiting factors of photosynthesis?

1512. What is the general chemical equation of photosynthesis? Why doesn't that equation clearly show the real origin of the molecular oxygen liberated?

1513. Why is the nickname “dark reactions” not entirely correct for the chemical stage of photosynthesis?

1514. What are the roles of NADPH and ATP in the chemical stage of photosynthesis?

1515. Which are the subproducts of the photochemical stage that are essential for the chemical stage of photosynthesis?

1516. Where do the photochemical and the chemical stages of photosynthesis occur?

1517. Photosynthesis is the most important producer of molecular oxygen (O2) on our planet. From which molecule do oxygen atoms liberated by photosynthesis come?

1518. What is NADP and NADPH?

1519. What are the divisions of white light according to the electromagnetic spectrum? Which are the two most efficient colors for photosynthesis?

1520. What is an example of a lab experiment that shows the variation of the photosynthesis efficiency in relation to different photic energy frequencies to which the reaction is exposed?

1521. What is the complete chemical equation of photosynthesis?

1522. Why is it said that during photosynthesis carbon dioxide is enriched to form glucose?

1523. In sulfur photosynthetic bacteria what is the molecule that donates hydrogen for photosynthesis?

1524. What are the chemical substances produced by water photolysis? What is the destination of each of those substances?

1525. Is it correct to consider water decomposition by the action of light the basis of the photosynthesis process?

1526. How is the photic energy absorbed by chlorophyll transfered to ATP molecules in photophosphorylation? How will be the resulting ATP used?

1527. What are the processes of the photochemical stage of the photosynthesis process?

1528. What are the stages into which photosynthesis is divided?

1529. What is ADP phosphorylation? What respectively are photophosphorylation and oxidative phosphorylation?

1530. What do ATP and ADP mean? What are the roles of these molecules for the cellular energetic metabolism?

1531. In which chloroplast structure are chlorophyll molecules found?

1532. What are the main structures of chloroplasts?

1533. How can the hypothesis that asserts that chloroplasts as well as mitochondria were primitive prokaryotes that associated in mutualism with primitive anaerobic eukaryotic cells be corroborated?

1534. How do chloroplasts multiply?

1535. Which chemical element is central in the chlorophyll molecule?

1536. What is the chemical equation of photosynthesis?

1537. Are there chloroplasts in cyanobacteria?

1538. How is light from the sun transformed into chemical energy to be used by the living beings on earth?

1539. Which are the living beings that carry out photosynthesis? Which is the cell organelle responsible for the absorption of light for the photosynthesis process in plants and algae?

1540. What is the primary source of energy for living beings on earth?

1541. During which meiosis division does ploidy reduction occur? Does ploidy reduction occur in mitosis?

1542. What are the respective functions of the separation of homologous chromosomes and of the separation of identical chromatids in meiosis?

1543. What are the periods of the second meiotic division?

1544. Is there interphase again between meiosis I and meiosis II?

1545. What are the “chiasms” of homologous chromosomes seen in prophase I?

1546. What is crossing over? In which period of meiosis does this event occur?

1547. In which meiotic division does the separation of identical chromatids occur? After the end of this process what are the ploidies of the new cells?

1548. In which period of meiosis does the pairing of homologous chromosomes occur?

1549. What are the periods of the first meiotic division?

1550. In which meiotic division does the separation of the homologous occur? What are the ploidies of the generated cells after the end of that process?

1551. How many cells are made after meiosis I and meiosis II?

1552. What are the two divisions of meiosis? What are the main events that occur in those divisions?

1553. Is the interphase of meiosis different from the interphase of mitosis?

1554. What is the difference between sexual spores and gametes? Do humans present sexual spores or gametes?

1555. Why is meiosis important for the maintenance of the normal quantity of chromosomes of a species with sexual reproduction?

1556. What are the respective ploidies of gamete, zygote and somatic cells in a species with gametic meiosis?

1557. For the biological diversity is mitosis or meiosis the more important process?

1558. Concerning their biological function what is the difference between mitosis and meiosis?

1559. Concerning their final products (daughter cells and their ploidies) what are the differences between mitosis and meiosis?

1560. Can mitosis occur in haploid (n) cells? And in triploid cells?

1561. What are the differences between astral and anastral mitosis?

1562. How does the quantity of genetic material vary within the cell during the sequential phases of the cell cycle?

1563. Why is it important for chromosomes to be condensed during mitosis and decondensed during interphase?

1564. During mitotic anaphase is there separation of homologous chromosomes or separation of identical chromatids?

1565. What is the name of the cytoplasm division in the end of mitosis? What are the differences in this process between animal and plant cells?

1566. What are the main events of the third mitotic period?

1567. What are the main events of the final mitotic period?

1568. What are the main events of the second mitotic period?

1569. What is the mitotic apparatus?

1570. What are centrioles? In which type of cell are they present?

1571. What are the main events of the first mitotic period?

1572. Into which periods is mitosis divided?

1573. Does mitosis properly occur before or after the interphase? Is it a mere “point of view” issue?

1574. What are the events that mark the beginning and the end of the third interphase period? What happens in the cell in this period?

1575. What are the events that mark the beginning and the end of the second interphase period? What happens in the cell in this period?

1576. What are the events that mark the beginning and the end of the first interphase period? What happens within the cell in this period?

1577. In general which phase of the cell cycle has longer duration?

1578. What are the three periods into which interphase is divided?

1579. Is cell division happening during the entire cell cycle? What is interphase?

1580. What is cell cycle?

1581. What is cellular regeneration? How is mitosis related to this process?

1582. Is the internal epithelium of the bowel the same as it was one month ago?

1583. What is the uncontrolled mitotic process that occurs as disease in pluricellular beings called?

1584. How does mitosis participate in the growth of pluricellular organisms?

1585. What are some examples of organs and tissues where mitosis is more frequent, less frequent or practically absent?

1586. Why in some cases is mitosis a synonym of reproduction?

1587. What is the importance of mitosis for the embryonic development?

1588. What is mitosis? What is the importance of mitosis?

1589. Of which structures is the nuclear membrane composed?

1590. What is the nucleolus?

1591. Do phylogenetically proximal species have cells with proximal chromosome counts?

1592. How many chromosomes does a human normal haploid cell have? How many chromosomes does a human normal diploid cell have? How many are the sex chromosomes within each of them?

1593. What is the other name given to sex chromosomes? What is the function of sex chromosomes?

1594. Can two normal individuals of the same species with sexual reproduction have identical genomes and identical karyotypes? How is the human karyotype usually represented?

1595. What is the difference between the concepts of karyotype and genome?

1596. What are homologous chromosomes? Which are the human cells that do not have homologous chromosomes?

1597. What are the primary and the secondary constrictions of a chromosome? What is the other name given to the secondary constriction?

1598. How is the chromosome region where the centromere is located called? How are chromosomes classified in relation to the position of their centromere?

1599. What is the structure that maintains identical chromatids bound?

1600. How are the concepts of chromosome, chromatin and chromatids related? In which phase of the cell cycle does DNA duplicate?

1601. In the phase when the cell is not dividing (interphase) is there activity within the cell nucleus?

1602. Of which substances is chromatin made?

1603. What is the relation between the concepts of chromatin and chromosome? Are euchromatin and heterochromatin part of chromosomes?

1604. Do all eukaryotic cells have nucleus and only one nucleus?

1605. What are heterochromatin and euchromatin?

1606. What are cells with a delimited nucleus called ? What are the main elements of the nucleus?

1607. What are some biological examples in which lysosomic enzymes play a fundamental role?

1608. What is autophagic intracellular digestion? Why is this type of intracellular digestion intensified in an organism undergoing starvation?

1609. What is heterophagic intracellular digestion? How is this process accomplished?

1610. What is intracellular digestion?

1611. What is the main cell organelle involved in cell digestion? What are the properties of that organelle that enable it to do the task?

1612. What is extracellular digestion?

1613. What are some examples of secretory cells?

1614. How do the rough endoplasmic reticulum and the Golgi apparatus act in the production and releasing of proteins?

1615. Which cell organelles are well-developed in secretory cells?

1616. What is meant by cellular secretion?

1617. What is cyclosis?

1618. What are some examples of movement created by the contraction of sarcomeres of the muscle cells?

1619. How does the amoeboid movement occur? What are examples of beings and cells that use such movements for locomotion?

1620. What are cilia and flagella? How do these structures acquire movement? What are some examples of ciliated and flagellated cells in humans?

1621. Of which substance are microtubules made? In which structures and cellular processes do microtubules participate?

1622. What are cell movements? How are these movements created?

1623. What is a cytoskeleton? What are its main constituents in animal cells?

1624. Of which substance are microfilaments made? What are the properties of these elements that give motility to cells?

1625. Why are salt and sugar used in the production of dried meat and dried fruits?

1626. What is deplasmolysis of plant cells?

1627. What is the formula of the DPD for withered (shrunken) plant cells? How is that situation possible?

1628. What are the values of DPD for plant cells under hypertonic, isotonic and hypotonic media?

1629. What does the formula DPD = SF – TP mean?

1630. What is the wall resistance of plant cells? Does this resistance facilitate or make difficult the entrance of water into the cell?

1631. What is meant by suction force of the plant cell? Does the suction force facilitate or make difficult the entrance of water into the cell?

1632. How does the plant cell wall react when it is placed under hypotonic medium?

1633. What are the two main types of endocytosis?

1634. What is mass transportation across the cell membrane?

1635. How does the sodium- potassium pump present in the cell membrane work? What is the importance of this protein for the cell?

1636. Which are the molecules that make possible active transport through membranes?

1637. What do facilitated diffusion and active transport have in common? What are the differences between them?

1638. What are some examples of biological activities in which osmosis plays an important role?

1639. How does facilitated diffusion present similarities with enzymatic chemical reactions?

1640. Without saturation of transport proteins and under the same concentration gradient how can the speed of simple diffusion be compared to the speed of facilitated diffusion?

1641. How does the intensity of facilitated diffusion vary in relation to the concentration of the moved substance? What is the limiting factor?

1642. How does the intensity of simple diffusion vary in relation to the concentration gradient of the moved substance?

1643. What is the difference between simple and facilitated diffusion? Facilitated by which type of molecule does the term “facilitated” mean?

1644. What is the energy source used in active transport through biological membranes?

1645. What are the three main types of passive transport?

1646. What is the relationship between concentration gradient and active and passive transport?

1647. What are differentiations of the cell membrane?

1648. What are the respective functions of phospholipids, proteins and carbohydrates of the cell membrane?

1649. What are the basic constituents of the cell membrane?

1650. Concerning permeability what type of membrane is the cell membrane?

1651. How are solutions classified according to their comparative tonicity?

1652. What is osmotic pressure?

1653. Can solutions with the same concentration of different solutes have different osmotic pressures?

1654. What is the difference between osmosis and diffusion?

1655. What is meant by concentration gradient? Is it correct to refer to “concentration gradient of water”?

1656. What is diffusion?

1657. What is diffusion?

1658. What is a membrane?

1659. What are plant cell vacuoles? What are their functions? What is the covering membrane of the vacuoles called?

1660. What is the function of the plant cell wall?

1661. Of what substance is the plant cell wall made? Of which monomer is it made?

1662. What is the path followed by the energy absorbed by plants to be used in photosynthesis?

1663. What are the colors (of the electromagnetic spectrum) absorbed by plants? What would happen to photosynthesis if the green light waves that reach a vegetable were blocked?

1664. What are chloroplasts? What are the main function of chloroplasts?

1665. What is the molecule responsible for the absorption of photic energy for photosynthesis? Where is that molecule located in photosynthetic cells?

1666. What are the functions of the cytoskeleton?

1667. What are the main components of the cytoskeleton?

1668. What is the endosymbiotic hypothesis about the origin of mitochondria? What are the molecular facts that support the hypothesis? To which other cellular organelles can the hypothesis also be applied?

1669. Why can mitochondria be considered the power plants of the aerobic cells?

1670. What are mitochondria? What is the basic morphology of these organelles and in which cells can they be found?

1671. Which are the cell organelles that participate in cell division and in the formation of cillia and flagella of some eukaryotic cells?

1672. What are the morphological, chemical and functional similarities and differences between lysosomes and peroxisomes?

1673. Why are lysosomes known as “the cleaners” of the cell waste?

1674. On which organelle of the cell structure does intracellular digestion depend? What is the chemical content of those organelles?

1675. A netlike membranous complex of superposed flat saccules with vesicles detaching from the extremities seen in electronic microscopy. What is the observed structure? What is its biological function?

1676. What is the difference between smooth and rough endoplasmic reticulum?

1677. Where in the cell can ribosomes be found? What is the main biological function of ribosomes?

1678. What are cytoplasmic inclusions?

1679. Of what substances is the nucleolus made? Is there a membrane around the nucleolus?

1680. What are the main cytoplasmic structures present in animal cells?

1681. What is the fluid that fills the nucleus called?

1682. What are the substances that constitute the chromatin? What is the difference between chromatin and chromosome?

1683. What are the main structures within the cell nucleus?

1684. What are the three main parts of a eukaryotic cell?

1685. Concerning the presence of the nucleus what is the difference between animal and bacterial cells?

1686. Which type of cell came first in evolution - the eukaryotic cell or the prokaryotic cell?

1687. Do membranes form only the outer wrapping of cells?

1688. What are the main respective constituents of cell walls in bacteria, protists, fungi and plants?

1689. What is the difference between plasma membrane and cell wall?

1690. What are the chemical substances that compose the plasma membrane?

1691. What is the plasma membrane of the cell? What are its main functions?

1692. Do bacteria cells have a nucleus? Are there any bacteria made of more than one cell?

1693. What are the two big groups into which cells are classified?

1694. In 1665 Robert Hooke, an English scientist, published his book Micrographia, in which he described that pieces of cork viewed under the microscope presented small cavities similar to pores which were filled with air

1695. What is cell theory? Are there living beings without cells?

1696. Do the phosphate and the pentose groups give homogeneity or heterogeneity to the nucleic acid chains?

1697. Is there any situation in which DNA is made based on a RNA template? What is the enzyme involved?

1698. Concerning their biological function what is the difference between DNA and RNA?

1699. What are the three main types of RNA? What is meant by heterogeneous RNA?

1700. What are similarities and differences between the transcription process and the replication processes?

1701. Does RNA molecule have two polynucleotide chains like DNA? What is the production of RNA called and what is the enzyme that catalyzes the process?

1702. Where can RNA be found within cells?

1703. Mistakes may happen during every copying process. The same is true for DNA replication. Are there correction systems in cells that try to fix those mistakes?

1704. Does DNA replication occur in cell division? One characteristic of the DNA molecule is its replication capability. What are the consequences of failures during DNA replication?

1705. As a result of DNA replication two DNA molecules come into existence. Why is it not correct to assert that two “new” DNA molecules are created? What is the name given to the process concerning that fact?

1706. What are the chemical bonds of the DNA molecule that are broken for the replication process to occur?

1707. How do the two complementary nucleotide chains of the DNA facilitate the replication process of the molecule?

1708. Why is it not correct to assert that DNA self- replicates?

1709. What is the name of the DNA duplication process? What is the main enzyme that participates in it?

1710. Which type of chemical bond maintains the pairing of each chain in the DNA molecule?

1711. What is the numeric relation between pyrimidine and purine bases in the DNA molecule? Is that relation valid in RNA molecules?

1712. What is the rule for the pairing of nitrogen-containing bases in the DNA molecule? And in the RNA? Is this last question appropriate?

1713. According to the Watson- Crick model how many polynucleotide chains does a DNA molecule have?

1714. Who were James Watson, Francis Crick and Maurice Wilkins?

1715. Bacteria are prokaryotic cells, i.e., they do not have a membrane-delimited nucleus. Eukaryotes have cells with a delimited nucleus. Where in these types of cells can DNA be found?

1716. Which are the nucleotides “portions” that bind in the formation of nucleic acids? What is meant by the 5’ and 3’ extremities of nucleic acids?

1717. Concerning the nitrogen- containing bases that participate in nucleotides, what is the difference between DNA and RNA?

1718. Of what units are nucleic acids constituted? What are the chemical entities that compose that unit?

1719. Into which two groups can the nitrogen-containing bases that form DNA and RNA be classified? What is the criterion used in that classification?

1720. What are pentoses? To what organic group do pentoses belong? Are nucleotides formed of only one type of pentose?

1721. What are nucleic acids? What is the historic origin of this name?

1722. What are zymogens?

1723. What is the action mechanism of the antibiotic penicillin?

1724. What are allosteric enzymes?

1725. What is the action mechanism of the antiretroviral drugs called protease inhibitors which are used against HIV infection?

1726. For the enzymatic reaction what is the effect of a substance with the same spatial conformation as an enzymatic substrate? How is this type of substance known?

1727. What is the relationship between vitamins and enzyme cofactors?

1728. Do enzymes act better under acid or basic pH?

1729. What are enzyme cofactors?

1730. Does pH affect the enzyme activity?

1731. Since pepsin is a gastric enzyme does it have an acid or basic optimum pH? What happens to pepsin when it passes into the duodenum?

1732. How is the cooling of organs and tissues for medical transplants associated with the effect of temperature upon enzymatic reactions?

1733. How does temperature affect the action of enzymes upon their substrates?

1734. How does the substrate concentration affect the speed of enzymatic reactions?

1735. How different are the graphic curve of the variation of the speed of a reaction as function of substrate concentration and the curve of variation of the speed of a reaction as function of temperature?

1736. What are the main factors that alter the speed of enzymatic reactions?

1737. What happens to a denatured enzyme regarding its functionality? How can that result be explained with the help of the lock and key model?

1738. On what structural level of the enzyme (primary, secondary, tertiary or quaternary) does the enzyme- substrate interaction depend?

1739. Why can it be said that the enzymatic action is highly specific?

1740. What is the activation center of an enzyme? Is it the key or the lock of the lock and key model?

1741. How does the formation of the enzyme-substrate complex explain the reduction of the activation energy of chemical reactions?

1742. What are the main theoretical models that try to explain the formation of the enzyme-substrate complex?

1743. What is meant by substrates of enzymatic reactions?

1744. What are enzymes? What is the importance of enzymes for living beings?

1745. Is there a difference between the initial and the final energy levels in catalyzed and non-catalyzed reactions?

1746. What amount of catalyst is consumed in the reaction it catalyzes?

1747. What are catalysts?

1748. What are respectively some remarkable functions of myosin, CD4, albumin, keratin, immunoglobulin, reverse transcriptase, hemoglobin and insulin?

1749. What is the difference between essential and natural amino acids?

1750. In sickle cell anemia, a hereditary disease, there is substitution of one amino acid by another in one of the four polypeptide chains of hemoglobin. In this case are all of the structural levels of the protein modified?

1751. Is it expected that a change in the primary, in the secondary or in the tertiary structure of a protein will produce more functional consequences?

1752. What are some factors that can lead to protein denaturation?

1753. How can denaturation be classified regarding its reversibility?

1754. What is protein denaturation? Is there any change in the primary structure when a protein is denatured?

1755. What is the quaternary structure of a protein? Do all proteins have quaternary structure?

1756. What is the tertiary structure of a protein? What are the main types of tertiary structure?

1757. What is the difference between the alpha-helix and the beta-sheet protein conformations?

1758. What is the secondary structure of a protein?

1759. What is the primary structure of a protein? What is the importance of the primary structure?

1760. What is the essential condition for a protein to be identical to another protein?

1761. Are proteins with the same number of each different amino acid that form them necessarily identical proteins?

1762. Are there different proteins made by the same total number of amino acids?

1763. Does the chemical reaction to unite amino acids incorporate or liberate atoms? What are the chemical entities incorporated or liberated in this reaction?

1764. Do the amine and the carboxyl groups attached to central carbons participate in the union between amino acids?

1765. Do the –H groups bound to the central carbons participate in the peptide bond?

1766. Do the –R groups bound to the central carbons participate in the union between amino acids?

1767. What is the binding between two amino acids called?

1768. How can the binding of two amino acids for the peptide formation be described?

1769. What is the importance of the –R group (variable radical) in an amino acid molecule?

1770. What is the structural flat representation of an amino acid molecule?

1771. What is the structural representation of a carboxyl group?

1772. How can amine groups be classified?

1773. Does every amino acid have a central carbon? To which organic group is that central carbon bound?

1774. How many are the known amino acids that form proteins in living beings?

1775. What is an oligopeptide? How is it different from a polypeptide?

1776. What is the constitutional unit of proteins?

1777. What is the importance of proteins for living beings?

1778. What are proteins? How can the protein diversity of living beings be explained?

1779. What is meant by saturation or unsaturation of oils and fats?

1780. Regarding solubility, how are lipids classified?

1781. Are organic solvents like benzene and ether polar or non-polar substances?

1782. What are hydrophobic molecules (or hydrophobic molecular regions)? What are hydrophilic molecules? How can they be characterized in relation to their polarity?

1783. What are steroids? What are some examples of steroids with a biological function?

1784. What are phospholipids?

1785. How are triglycerides made?

1786. What is the structural formula of glycerol? To which organic function do these molecules belong?

1787. What are the main types of lipids?

1788. What are the main biological functions of the polysaccharides?

1789. What are pentoses? What are the roles of pentoses in DNA and RNA molecules?

1790. What are hexoses? What are some examples of hexoses with important biological functions?

1791. What is the difference between monosaccharides and disaccharides? What are some examples of disaccharides and of monosaccharides that form them?

1792. What are monosaccharides, oligosaccharides and polysaccharides?

1793. What is the molecular formula of glucose? How can its structural formula be described?

1794. What are the organic chemical groups that characterize carbohydrates? How are carbohydrates classified according to the presence of those groups?

1795. What are the main biological functions in which chlorine ions participate?

1796. Why is iodine important for human beings?

1797. What is phosphorylation? What are some biological processes in which phosphorylation plays a critical role?

1798. What is the importance of magnesium for plants? What are the other main biological functions of magnesium?

1799. What is hemoglobin? What is the inorganic element that is fundamental in the composition of hemoglobin?

1800. What are the main biological processes in which calcium participates?

1801. How do mineral salts participate in enzymatic activity?

1802. Why is pH regulation important for living beings? How do mineral salts participate in this regulation?

1803. What is the role of mineral salts in the creation of electric tension (voltage) at the cellular level?

1804. How do mineral salts participate in osmotic regulation?

1805. What are the main negative ions found in living beings?

1806. Which are the main positive ions found in living beings?

1807. What are ions? What are the two types of molecules into which ions are classified?

1808. What are the main water properties that make water special for life?

1809. Can the heat capacity of water be considered small or large? What is the biological significance of that characteristic?

1810. What is the importance of water for enzymatic activity?

1811. Which kind of polarity do water-soluble and fat-soluble substances respectively have?

1812. Is water a polar or a non- polar molecule? What is the consequence of that characteristic for the function of water as solvent?

1813. Water has key participation in organic reactions. What are examples of two types of organic reactions in which water is respectively incorporated or liberated in the products of these reactions?

1814. What are the main biological functions of water?

1815. What is the approximate percentage (in mass) of water in the human body? Is this percentage expected to be larger in the adult or in the old individual?

1816. What are biopolymers?

1817. What are some examples of the control and informative function of organic molecules?

1818. What are some examples of the energetic function of organic molecules?

1819. What are some examples of the structural function of organic molecules?

1820. What are the main functions of the organic molecules for living beings?

1821. What are the most important organic molecules for living beings?

1822. What are mineral salts? Where in living beings can mineral salts be found?

1823. What are the most important inorganic molecular substances for living beings?

1824. Living beings are made of organic and inorganic substances. According to the complexity of their molecules how can each of those substances be classified?

1825. What are the chemical elements that form most of living biological matter?

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