1. Cell Development Review

2. Eukaryotic sexual life cycles show tremendous variation
Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores (A) I, IV, and V (C) II, III, and IV (B) I, II, and IV (D) II, IV, and V C

3. After telophase I of meiosis, the chromosomal makeup of each daughter cell is (A) diploid, and the chromosomes are each composed of a single chromatid. (B) diploid, and the chromosomes are each composed of two chromatids. (C) haploid, and the chromosomes are each composed of a single chromatid. (D) haploid, and the chromosomes are each composed of two chromatids. D

4. How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? (A) They have twice the amount of cytoplasm and half the amount of DNA. (B) They have half the number of chromosomes and half the amount of DNA. (C) They have the same number of chromosomes and half the amount of DNA. (D) They have half the number of chromosomes and one-fourth the amount of DNA. D

5. What could happen to the target cells in an animal that lack receptors for local regulators? A. They could compensate by receiving nutrients via an a factor. B. They could develop normally in response to neurotransmitters instead. C. They could divide but never reach full size. D. They would not be able to multiply in response to growth factors from nearby cells. E. Hormones would not be able to interact with target cells. D

6. When a cell releases a signal molecule into the environment and a number of cells in the immediate vicinity respond, this type of signaling is A. typical of hormones. B. autocrine signaling. C. paracrine signaling. D. endocrine signaling. E. synaptic signaling. c

7. Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to A. the active site of an allosteric enzyme in the cytoplasm that binds to a specific substrate. B. RNA specifying the amino acids in a polypeptide. C. a particular metabolic pathway operating within a specific organelle. D. an enzyme with an optimum pH and temperature for activity. E. genes making up a chromosome. A

8. Chiasmata are what we see under a microscope that let us know which of the following is occurring? A. Asexual reproduction B. Meiosis II C. Anaphase II D. Crossing over E. Separation of homologs D

9. Testosterone functions inside a cell by A
Testosterone functions inside a cell by A. acting as a signal receptor that activates ion-channel proteins. B. binding with a receptor protein that enters the nucleus and activates specific genes. C. acting as a steroid signal receptor that activates ion-channel proteins. D. becoming a second messenger that inhibits adenylyl cyclase. E. coordinating a phosphorylation cascade that increases glycogen metabolism. B

10. Which of the following describes the events of apoptosis. A
Which of the following describes the events of apoptosis? A. The cell dies, it is lysed, its organelles are phagocytized, its contents are recycled. B. Its DNA and organelles become fragmented, it dies, and it is phagocytized. C. The cell dies and the presence of its fragmented contents stimulates nearby cells to divide. D. Its DNA and organelles are fragmented, the cell shrinks and forms blebs, and the cell self-digests. E. Its nucleus and organelles are lysed, the cell enlarges and bursts. D

11. Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell? A. telophase B. anaphase C. prometaphase D. metaphase E. prophase B

12. Why do chromosomes coil during mitosis. A
Why do chromosomes coil during mitosis? A. to increase their potential energy B. to allow the chromosomes to move without becoming entangled and breaking C. to allow the chromosomes to fit within the nuclear envelope D. to allow the sister chromatids to remain attached B

13. This is the shortest part of the cell cycle: A. G0 B. G1 C. S D. G2 E
This is the shortest part of the cell cycle: A. G0 B. G1 C. S D. G2 E. M E

14. Density-dependent inhibition is explained by which of the following. A
Density-dependent inhibition is explained by which of the following? A. As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors. B. As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. C. As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. D. As cells become more numerous, more and more of them enter the S phase of the cell cycle. B

15. Eukaryotic sexual life cycles show tremendous variation
Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores A. I, IV, and V C. II, III, and IV B. I, II, and IV D. II, IV, and V C

16. Which number represents DNA synthesis? A. I B. II C. III D. IV E. V

17. G1 is represented by which number(s). A. I and V B. II and IV C. III D
G1 is represented by which number(s)? A. I and V B. II and IV C. III D. IV E. V A

18. Vinblastine is a standard chemotherapeutic drug used to treat cancer
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to A. disruption of mitotic spindle formation. B. inhibition of regulatory protein phosphorylation. C. suppression of cyclin production. D. myosin denaturation and inhibition of cleavage furrow formation. A

19. How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? A. They have twice the amount of cytoplasm and half the amount of DNA. B. They have half the number of chromosomes and half the amount of DNA. C. They have the same number of chromosomes and half the amount of DNA. D. They have half the number of chromosomes and one-fourth the amount of DNA. D

20. Meiosis II is similar to mitosis in that A
Meiosis II is similar to mitosis in that A. sister chromatids separate during anaphase. B. DNA replicates before the division. C. the daughter cells are diploid. D. homologous chromosomes synapse. E. the chromosome number is reduced. A

21. In general, a signal transmitted via phosphorylation of a series of proteins A. brings a conformational change to each protein. B. requires binding of a hormone to a cytosol receptor. C. cannot occur in yeasts because they lack protein phosphatases. D. requires phosphorylase activity. E. allows target cells to change their shape and therefore their activity. A

22. The termination phase of cell signaling requires which of the following? A. removal of the receptor B. activation of a different set of relay molecules C. converting ATP to cAMP D. reversing the binding of signal molecule to the receptor E. apoptosis D

23. How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle? A. The daughter cells have half the amount of cytoplasm and half the amount of DNA. B. The daughter cells have half the number of chromosomes and half the amount of DNA. C. The daughter cells have the same number of chromosomes and half the amount of DNA. D. The daughter cells have the same number of chromosomes and the same amount of DNA. E. The daughter cells have the same number of chromosomes and twice the amount of DNA. D

24. Taxol is an anticancer drug extracted from the Pacific yew tree
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Specifically, taxol must affect A. the fibers of the mitotic spindle. B. anaphase. C. formation of the centrioles. D. chromatid assembly. E. the S phase of the cell cycle. A

25. If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will A. move directly into telophase. B. complete the cycle and divide. C. exit the cycle and switch to a nondividing state. D. show a drop in MPF concentration. E. complete cytokinesis and form new cell walls. B

26. Which of the following describe(s) cyclin-dependent kinase (Cdk). I
Which of the following describe(s) cyclin-dependent kinase (Cdk)? I. Cdk is inactive, or "turned off," in the presence of cyclin. II. Cdk is present throughout the cell cycle. III. Cdk is an enzyme that attaches phosphate groups to other proteins. A. I only D. II and III only B. II only E. I, II, and III C. I and II only D

27. The karyotype of one species of primate has 48 chromosomes
The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following? A. Mitosis in her ovary B. Metaphase I of one meiotic event C. Telophase II of one meiotic event D. Telophase I of one meiotic event E. Either anaphase I or II E

28. Which of the following happens at the conclusion of meiosis I. A
Which of the following happens at the conclusion of meiosis I? A. Homologous chromosomes are separated. B. The chromosome number per cell is conserved. C. Sister chromatids are separated. D. Four daughter cells are formed. E. The sperm cells elongate to form a head and a tail end. A

29. Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesions. Such molecules must have which of the following properties? A. They must persist throughout the cell cycle. B. They must be removed before meiosis can begin. C. They must be removed before anaphase can occur. D. They must reattach to chromosomes during G1. E. They must be intact for nuclear envelope reformation. C

30. Minutes Spent in Cell Cycle Phases The data were obtained from a study of the length of time spent in each phase of the cell cycle by cells of three eukaryotic organisms designated beta, delta, and gamma. Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that A. gamma contains more DNA than beta. B. beta and gamma contain the same amount of DNA. C. beta contains more RNA than gamma. D. gamma contains 48 times more DNA and RNA than beta. E. beta is a plant cell and gamma is an animal cell. A

31. different cell types of an organism, determined the relative DNA
You have isolated
DNA from three
different cell types of
an organism,
determined the relative DNA
content for each type, and plotted the results.
Which sample might represent an animal cell in G2 phase of the cell cycle?
A. I D. Either I or II
B. II E. Either II or III
C. III B

32. You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results. Which sample might represent a sperm cell? A. I D. Either I or II B. II E. Either II or III C. III C

33. You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results. Which sample of DNA might be from a nerve cell arrested in G0 of the cell cycle? A. I D. Either I or II B. II E. Either II or III C. III A

34. 1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus 2. Alignment of tetrads at the metaphase plate 3. Separation of sister chromatids 4. Separation of the homologues; no uncoupling of the centromere 5. Synapsis; chromosomes moving to the middle of the cell in pairs From the descriptions above, which of the following is the order that most logically illustrates a sequence of meiosis? A. 1, 2, 3, 4, 5 D. 4, 5, 2, 1, 3 B. 5, 4, 2, 1, 3 E. 5, 2, 4, 3, 1 C. 5, 3, 2, 4, 1 E

35. An inhibitor of phosphodiesterase activity would have which of the following effects? A. block the response of epinephrine B. decrease the amount of cAMP in the cytoplasm C. block the activation of G proteins in response to epinephrine binding to its receptor D. prolong the effect of epinephrine by maintaining elevated cAMP levels in the cytoplasm E. block the activation of protein kinase A D

36. Lipid-soluble signal molecules, such as testosterone, cross the membranes of all cells but affect only target cells because A. only target cells retain the appropriate DNA segments. B. intracellular receptors are present only in target cells. C. most cells lack the Y chromosome required. D. only target cells possess the cytosolic enzymes that transduce the testosterone. E. only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor. B

37. Consider this pathway: epinephrine  G protein-coupled receptor  G protein  adenylyl cyclase  cAMP. Identify the second messenger. A. cAMP B. G protein C. GTP D. adenylyl cyclase E. G protein-coupled receptor A

38. If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase? A. 1 B. 2 C. 4 D. 8 E. 16 E

39. Which of the following are primarily responsible for cytokinesis in plant cells? A. kinetochores B. Golgi-derived vesicles C. actin and myosin D. centrioles and basal bodies E. cyclin-dependent kinases B

40. Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei re-forming on either side of the cell plate. This cell is most likely A. an animal cell in the process of cytokinesis. B. a plant cell in the process of cytokinesis. C. an animal cell in the S phase of the cell cycle. D. a bacterial cell dividing. B

41. A given organism has 46 chromosomes in its karyotype
A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A. It must be human. B. It must be a primate. C. It must be an animal. D. It must be sexually reproducing. E. Its gametes must have 23 chromosomes. E

42. Chromatids are separated from each other. A
Chromatids are separated from each other. A. The statement is true for mitosis only. B. The statement is true for meiosis I only. C. The statement is true for meiosis II only. D. The statement is true for mitosis and meiosis I. E. The statement is true for mitosis and meiosis II. E

43. A tetrad includes which of the following sets of DNA strands. A
A tetrad includes which of the following sets of DNA strands? A. Two single-stranded chromosomes that have synapsed B. Two sets of sister chromatids that have synapsed C. Four sets of sister chromatids D. Four sets of unique chromosomes E. Eight sets of sister chromatids B

44. Caffeine is an inhibitor of phosphodiesterase
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of A. phosphorylated proteins. B. GTP. C. cAMP. D. adenylyl cyclase. E. activated G proteins. C

45. Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because A. they are species specific. B. they always lead to the same cellular response. C. they amplify the original signal many fold. D. they counter the harmful effects of phosphatases. E. the number of molecules used is small and fixed. C

46. One inhibitor of cGMP is Viagra
One inhibitor of cGMP is Viagra. It provides a signal that leads to dilation of blood vessels and increase of blood in the penis, facilitating erection. cGMP is inhibited, therefore the signal is prolonged. The original signal that is now inhibited would have A. hydrolyzed cGMP to GMP. B. hydrolyzed GTP to GDP. C. phosphorylated GDP. D. dephosphorylated cGMP. E. removed GMP from the cell. A

47. If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested? A. anaphase B. prophase C. telophase D. metaphase E. interphase D

48. The somatic cells derived from a single-celled zygote divide by which process? A. meiosis B. mitosis C. replication D. cytokinesis alone E. binary fission B

49. You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify metaphase I cells on the slide? A. A visible nuclear envelope B. Separated sister chromatids at each pole of the cell C. Tetrads lined up at the center of the cell D. A synaptonemal complex E. A cleavage furrow C

50. A mutation results in a cell that no longer produces a normal protein kinase for the M phase checkpoint. Which of the following would likely be the immediate result of this mutation? A. The cell would prematurely enter anaphase. B. The cell would never leave metaphase. C. The cell would never enter metaphase. D. The cell would never enter prophase. E. The cell would undergo normal mitosis, but fail to enter the next G1 phase. E