Ch. 16 The Eukaryotic Cell Cycle, Mitosis, and Meiosis Study Questions and Answer Key

12) A mutation occurs in a gene that encodes a G1 cyclin, such that the protein is unable to bind to its CDK. How will this affect the cell cycle? A) The cell will be stuck in G1 and will not advance through the cell cycle. B) The cell will replicate its DNA, but will be unable to progress through mitosis. C) The cell will rapidly replicate its DNA and progress through mitosis, causing uncontrolled cell division, and lead to cancer. D) The cell will proceed thru mitosis without replicating its DNA. E) The cell will proceed to the S phase, and DNA repair enzymes will repair the mutated cyclin when it replicates the DNA.

A) The cell will be stuck in G1 and will not advance through the cell cycle.

46) The life cycle of sexually reproducing organisms includes A) mitosis and meiosis. B) mitosis, meiosis, and fusion of the gametes. C) meiosis and fusion of gametes. D) only mitosis. E) only meiosis.

B) mitosis, meiosis, and fusion of the gametes.

44) Sexual life cycles include both haploid and diploid stages.

True

14) The following graph represents the concentration of cyclins over the course of the cell cycle. Which of the following statements is TRUE regarding the cell cycle where the red arrow is pointing? A) CDK proteins are actively phosphorylating proteins that are involved in DNA replication. B) CDK proteins are actively phosphorylating proteins that are responsible for assembling the mitotic spindle. C) CDK proteins are actively phosphorylating and activating cyclins so that the cell will prepare to replicate its DNA. D) CDK proteins are actively phosphorylating and activating cyclins so that the cell will properly assemble the spindle apparatus. E) CDK proteins are actively phosphorylating regions of the DNA that need to be targeted for DNA repair.

A) CDK proteins are actively phosphorylating proteins that are involved in DNA replication.

53) A male who inherits an extra X chromosome will have A) Klinefelter syndrome. B) Turner syndrome. C) Down syndrome. D) Polyploid syndrome. E) Edward syndrome.

A) Klinefelter syndrome.

45) Why must the life cycle of sexually reproducing species alternate between haploid and diploid stages? A) Meiosis must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation. B) Mitosis must occur at some point in the life cycle to prevent a reduction of chromosomes in each generation. C) The diploid stage allows for genetic recombination. D) Meiosis must occur at some point in the life cycle to prevent a reduction of chromosomes in each generation. E) Haploid cells cannot grow independently of diploid cells.

A) Meiosis must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation.

31) During crossing over in meiosis, an unequal exchange of genetic material occurs. This would most likely produce A) a deficiency in one homologue and a duplication in the other homologue. B) a deficiency in both homologues. C) a deficiency in one homologue and an inversion in the other homologue. D) a reciprocal translocation. E) a duplication in one homologue and an inversion in the other homologue.

A) a deficiency in one homologue and a duplication in the other homologue.

19) The centromere A) is a region of DNA where sister chromatids associate. B) is a group of proteins that attach to the kinetochore. C) is only present when chromosomes are highly compacted. D) is a group of proteins that attach to the mitotic spindle. E) is not present on the chromosomes of the daughter cells until anaphase.

A) is a region of DNA where sister chromatids associate.

29) Synaptonemal complexes form during A) prophase of meiosis I. B) prophase of meiosis II. C) prophase of meiosis I and meiosis II. D) prometaphase of meiosis I. E) prometaphase of meiosis II.

A) prophase of meiosis I.

50) Consider a cell in which nondisjunction occurs for all chromosomes during meiosis I. What would be the result of this event? A) two aneuploid gametes, each with an extra set of chromosomes B) two haploid gametes and one aneuploid gamete with an extra set of chromosomes C) four aneuploid gametes D) four haploid gametes E) two haploid gametes and two polyploid gametes

A) two aneuploid gametes, each with an extra set of chromosomes

32) Consider an organism whose karyotype shows it to have a total of 60 chromosomes. How many chromosomes would be contained in the sperm of this organism? A) 23 B) 30 C) 46 D) 60 E) 90

B) 30

55) In a tetraploid species, a euploid individual would have ________ sets of chromosomes. A) 2 B) 4 C) 6 D) 8 E) 2n+2

B) 4

15) The following graph represents the concentration of cyclins over the course of the cell cycle. Which of the following statements is TRUE regarding the phase of the cell cycle where the green arrow is pointing? A) At this point in the cell cycle, the cell has determined that the DNA is intact and environmental conditions are favorable for DNA replication. B) At this point in the cell cycle, chromosomes are properly aligned on the metaphase plate and are beginning to separate. C) At this point in the cell cycle, DNA has already been replicated correctly and the cell is preparing for mitosis. D) At this point in the cycle the cell is determining if environmental conditions are favorable for growth and proliferation. E) At this point in the cycle the cell is continuing to grow and make abundant tubulin proteins.

B) At this point in the cell cycle, chromosomes are properly aligned on the metaphase plate and are beginning to separate.

5) Put the following steps in the procedure for producing a karyotype in the correct order. I. Cells are visualized under the microscope. II. Cells are stimulated to divide. III. Homologues are organized into sets by matching size and banding patterns. IV. The cells are exposed to a hypotonic solution. V. Cells are stained and placed on a microscope slide. A) I, II, IV, V, III B) II, IV, V, I, III C) IV, II, V, I, III D) IV, V, II, I, III E) II, IV, I, V, III

B) II, IV, V, I, III

54) Why are sex chromosome aneuploidies less detrimental than autosomal aneuploidies? A) Sex chromosomes do not contain genes that are important for anything other than sex determination. B) In females, all but one X-chromosome is inactivated; in males, the Y chromosome contains very few genes, so extra or missing copies do not cause huge abnormalities. C) Gene expression of the sex chromosomes is not dosage-dependent as it is for the autosomes. D) Sex chromosomes are only found in gametes, they do not occur in diploid cells. E) All of the answers are correct.

B) In females, all but one X-chromosome is inactivated; in makes, the Y chromosome contains very few genes, so extra or missing copies do not cause huge abnormalities.

49) Consider a diploid species where n = 5. If an individual of this species was found to have 11 chromosomes, it would be categorized as A) polyploid. B) aneuploid. C) tetraploid D) monosomic. E) triploid.

B) aneuploid.

21) Which of the following is NOT a part of the mitotic spindle apparatus in plants? A) centrosome B) centrioles C) tubulin proteins D) kinetochore microtubules E) astral microtubules

B) centrioles

38) The formation of the bivalent during meiosis A) is required for the pairing of homologous chromosomes. B) contributes to the genetic diversity of a species. C) ensures that the resulting haploid cells will have the same combination of homologous chromosomes as the original diploid cell. D) aids the alignment of sister chromatids in a single row along the metaphase plate. E) occurs during meiosis I and meiosis II.

B) contributes to the genetic diversity of a species.

48) Which of the following mutations will NOT alter the amount of genetic material of a chromosome? A) duplication B) inversion C) simple translocation D) deficiency E) inversion and simple translocation

B) inversion

2) DNA associates very tightly with nucleosomes because A) DNA can form covalent bonds with histone proteins. B) negative charges on DNA are attracted to the positive charges of the histone proteins. C) the histone tails wrap tightly around the DNA double helix. D) the amino acids of histone proteins are largely acidic, while DNA molecules are basic. E) histone H1 tightens the coils of DNA that is wrapped around the nucleosome.

B) negative charges on DNA are attracted to the positive charges of the histone proteins.

28) In mitosis, the main difference between plant and animal cells is that A) plants do not undergo cytokinesis. B) plants produce a cell plate to segregate the daughter nuclei, while animals form a cleavage furrow. C) plants have a central vacuole, while animal cells do not. D) plants produce a cell membrane in cytokinesis, while animals form a cell plate. E) in plants, kinetochore microtubules shorten and draw chromosomes toward the poles; in animals, polar microtubules lengthen to push chromatids apart.

B) plants produce a cell plate to segregate the daughter nuclei, while animals form a cleavage furrow.

1) Cytogenetics is A) a photographic representation of chromosome. B) the field of genetics that involves microscopic examination of the chromosomes and cell division. C) the sorting process to divide one cell nucleus into two nuclei. D) the process in which the two nuclei are segregated into separate daughter cells. E) the process by which the haploid cells are produced from a cell that was originally diploid.

B) the field of genetics that involves microscopic examination of the chromosomes and cell division.

39) A species that three sets of homologous chromosomes can have ________ different combinations of chromosomes in its gametes. A) 3 B) 6 C) 8 D) 27 E) 64

C) 8

23) Which of the following occurs during metaphase? A) Heterochromatin is converted to euchromatin. B) Chromosomes are about 30 nm wide. C) Chromosomes are much shorter than they were in interphase. D) Chromosomes undergo gene transcription. E) The "beads on a string" structure is visible.

C) Chromosomes are much shorter than they were in interphase.

25) Place the following events of mitosis in the correct order. I. Sister chromatids align on the metaphase plate. II. The cleavage furrow forms. III. The nuclear membrane breaks up. IV. Sister chromatids condense. V. Sister chromatids separate. A) I, II, III, IV, V B) III, IV, I, V, II C) IV, III, I, V, II D) III, II, I, IV, V E) IV, I, III, V, II

C) IV, III, I, V, II

11) Which of the following statements regarding the G1 (first gap) phase of the eukaryotic cell cycle is NOT true? A) Most cells spend the majority of their lives in the G1 phase of the cell cycle. B) Cells that are terminally differentiated and will not divide mitotically might exit the G1 phase and enter the G0 phase. C) If environmental conditions are favorable during the G1 phase, G1 cyclins are degraded causing the cell to prepare to replicate its DNA. D) The G1 phase is only part of interphase. E) If DNA is heavily damaged, checkpoint proteins will delay the cell cycle; the damage will either be fixed or cell division will be permanently stopped.

C) If environmental conditions are favorable during the G1 phase, G1 cyclins are degraded causing the cell to prepare to replicate its DNA.

8) Chromosomes are replicated during the ________ phase. A) G1 B) G2 C) S D) M E) meta-

C) S

20) Which of the following statements about sister chromatids is TRUE? A) Sister chromatids are produced during mitosis. B) Sister chromatids are held together by complementary base pairing of DNA at the centromere. C) Sister chromatids are exact copies of each other and are formed just prior to cell division. D) After mitosis, sister chromatids contain the same genes, but they may have different alleles. E) All of these statements about sister chromatids are TRUE.

C) Sister chromatids are exact copies of each other and are formed just prior to cell division.

22) Colchicine is a toxin that binds to tubulin proteins and prevents microtubules from elongating. What effect might this have on dividing cells? A) Cells will be able to complete mitosis, but cytokinesis will not occur. B) Chromosomes will not be able to condense, so mitosis will not occur. C) Sister chromatids will not be properly separated into separate daughter cells. D) Replicated chromosomes will not be able to stick together, so sister chromatids will not properly sort into daughter nuclei. E) The cell will not be able to move past the restriction point, so DNA will not be replicated.

C) Sister chromatids will not be properly separated into separate daughter cells.

51) Most human embryos that are aneuploid A) result in Down's syndrome. B) result in sterility. C) are spontaneously aborted in the first trimester. D) can develop and survive to adulthood. E) are usually the result of increased nondisjunction in the gametes of older men.

C) are spontaneously aborted in the first trimester.

42) The major way that meiosis II differs from mitosis is that A) in meiosis II, the homologous sister chromatids align at the metaphase plate as a tetrad. B) in meiosis II, a pair of sister chromatids move to the pole. C) in meiosis II, the daughter cells are haploid. D) in meiosis II, a synaptonemal complex is formed. E) in meiosis II, the homologues separate.

C) in meiosis II, the daughter cells are haploid.

34) Meiosis I produces ________, and meiosis II produces ________ cells. A) two diploid, two haploid B) two diploid, 4 haploid C) two haploid, 4 haploid D) two haploid, two haploid E) two somatic, two gametic

C) two haploid, 4 haploid

3) Humans have ________ different types of autosomes. A) 46 B) 44 C) 23 D) 22 E) 11

D) 22

13) The following graph represents the concentration of cyclins over the course of the cell cycle. Which of the following statements is TRUE regarding the phase of the cell cycle where the red arrow is pointing? A) At this point in the cell cycle, all sister chromatids are fully formed. B) At this point in the cell cycle, DNA has already been replicated correctly. C) At this point in the cell cycle, chromosomes are properly aligned on the metaphase plate and are beginning to separate. D) At this point in the cell cycle, the cell is determining if conditions are favorable for cell division. E) At this point in the cycle the cell is continuing to grow and make abundant tubulin proteins.

D) At this point in the cell cycle, the cell is determining if conditions are favorable for cell division.

10) Which of the following is NOT a checkpoint that controls the progression of the cell cycle? A) Cyclins and cyclin-dependent kinases are proteins that are responsible for advancing a cell through the phases of the cell cycle. B) The G2 checkpoint checks for DNA damage and determines if all of the DNA is replicated. C) The metaphase checkpoint determines if all chromosomes are attached to the spindle apparatus. D) Cytokinesis involves the formation of cleavage furrow to separate the cells. E) The restriction point determines if conditions are favorable for cell division and if the DNA is undamaged.

D) Cytokinesis involves the formation of cleavage furrow to separate the cells.

52) When a gamete that is lacking a sex chromosome due to nondisjunction has fused with a gamete carrying an X chromosome, this type of abnormality leads to ________. A) Triple X syndrome B) Down Syndrome C) Edward Syndrome D) Turner syndrome E) Klinefelter Syndrome

D) Turner Syndrome

7) Which of the following statements about the cell cycle is correct? A) The cell cycle is a sequence of replications and divisions that produces new cells. B) The phases of the cell cycle are G1, S, and M phases. C) In actively dividing cells, the S and G2 phases are collectively known as interphase. D) When the S phase of the cell cycle is finished, a cell has twice as many chromatids as the number of chromosomes in the G1 phase. E) During G2 phase, the cell grows and copies its chromosomes in preparation for cell division.

D) When the S phase of the cell cycle is finished, a cell has twice as many chromatids as the number of chromosomes in the G1 phase.

40) The process by which haploid cells are produced from diploid cells is called A) sexual reproduction. B) mitosis. C) fertilization. D) meiosis. E) reduction.

D) meiosis.

56) Polyploidy in plants A) is very common. B) allows for adaptation to diverse environments. C) may alter the levels of gene expression. D) allows humans to create plants with unusual flowers. E) All of these statements are true regarding polyploidy in plants.

E) All of these statements are true regarding polyploidy in plants.

16) The following graph represents the concentration of cyclins over the course of the cell cycle. Which of the following statements is TRUE regarding the phase of the cell cycle where the blue arrow is pointing? A) At this point in the cell cycle, the cell has determined that the DNA is intact, that environmental conditions are favorable, and it is preparing for DNA replication. B) At this point in the cell cycle, chromosomes are properly aligned on the metaphase plate and are beginning to separate. C) At this point in the cell cycle, DNA has already been replicated and divided into two daughter nuclei. D) At this point in the cycle the cell is determining if environmental conditions are favorable for growth and proliferation. E) At this point in the cycle the cell is continuing to grow and make abundant tubulin proteins

E) At this point in the cycle the cell is continuing to grow and make abundant tubulin proteins

27) What does not happen in the cytokinesis of plant cells? A) Vesicles from the Golgi apparatus move along microtubules and fuse form cell plate. B) Cell wall forms between the two daughter cells.. C) The two nuclei are segregated into separate daughter cells. D) When the vesicles fuse, their membranes contribute to the formation of plasma membrane on either side of the cell plate. E) Formation of cleavage furrow to separate the cells.

E) Formation of cleavage furrow to separate the cells.

18) Which of the following statements is FALSE concerning sister chromatids? A) The formation of sister chromatids doubles the amount of DNA in a cell. B) Sister chromatids consist of two identical copies of a single homologue. C) Sister chromatids are held together at the centromere by cohesion proteins. D) Sister chromatids are formed during the S phase of the cell cycle. E) Sister chromatids separate during telophase.

E) Sister chromatids separate during telophase

36) Sister chromatids separate during A) prophase of meiosis I. B) metaphase of meiosis I. C) metaphase of meiosis II. D) prometaphase of meiosis I. E) anaphase of meiosis II.

E) anaphase of meiosis II

4) You prepare the first ever karyotype of an endangered species of frog. Upon examination you find that all the chromosomes are metacentric. This is going to make it difficult to identify A) which is the p arm of the chromosome. B) which is the q arm of the chromosome. C) the unique G banding for each chromosome. D) if the chromosomes are telocentric. E) both the p and q arms of the chromosome.

E) both the p and q arms of the chromosome.

47) A chromosome with the centromere located two-thirds of the distance from its end could be classified as A) metacentric. B) submetacentric. C) acrocentric. D) telocentric. E) either submetacentric or acrocentric.

E) either submetacentric or acrocentric.

35) At the end of meiosis I A) cells are haploid. B) cells are diploid. C) the homologous pairs are in separate cells. D) the cells are diploid and the homologous pairs are in separate cells. E) the cells are haploid and the homologous pairs are in separate cells.

E) the cells are haploid and the homologous pairs are in separate cells.

17) How are sister chromatids connected to each other? A) through complementary base pairing of DNA at the centromere B) through centromere proteins that are attracted to each other by opposite charges C) through activated cyclin/CDK complexes D) through the centrioles E) through cohesion proteins

E) through cohesion proteins

24) Mitotic cell division is never used by organisms as a means of reproduction.

False

26) During prometaphase, the sister chromatids organize into a single row in the center of the cell.

False

30) Homologous chromosomes are identical copies of each other.

False

41) For any given species, cells in metaphase II of meiosis would contain two times more genetic material than cells in metaphase of mitosis.

False

6) The karyotype of a normal human male would show a total of 23 pairs of homologous chromosomes.

False

9) If a cell contains 20 chromosomes in G1, it will contain 40 chromosomes at the end of S.

False

33) A cell undergoing meiosis that contains sister chromatids may be either haploid or diploid.

True

37) One major difference between metaphase I and metaphase II is the presence or absence of bivalents.

True

43) In a haploid dominant species A) the multicellular organism is diploid and only the gametes are haploid. B) the multicellular organism is haploid and only the gametes are diploid. C) diploid cells are produced by mitosis and haploid cells are produced by meiosis. D) the multicellular organism is diploid, and only the zygote is haploid. E) the multicellular organism is haploid, and only the zygote is diploid

e) the multicellular organism is haploid, and only the zygote is diploid