Genetics Test 2 Ch. 3

Question 1

1) Mitosis is a process of cell division that results in ________. 1)<br></br>A) two unique daughter cells<br></br>B) two identical daughter cells<br></br> <br></br>C) four unique daughter cells<br></br>D) three identical daughter cells E) four identical daughter cells

Answer 1

Answer: B

Question 2

2) During which phase of the cell cycle does the cell actively transcribe and translate protein products 2) necessary for normal cellular structure and function while not advancing the cell cycle?<br></br>A) Gap 1 phase<br></br> <br></br>B) Gap 2 phase C) Interphase<br></br>D) Metaphase<br></br>E) Gap 0 phase

Answer 2

Answer: C

Question 3

3) During which phase of the cell cycle does the cell initiate replication of its nuclear DNA? 3) A) Gap 1 phase<br></br>B) Metaphase<br></br> <br></br>C) Gap 2 phase<br></br>D) Synthesis phase E) Gap 0 phase

Answer 3

Answer: D

Question 4

4) After which stage or phase of the cell cycle does cytokinesis occur? 4)<br></br>A) G1 B) G2 C) M phase D) S E) G0

Answer 4

Answer: C

Question 5

5) Certain kinds of cells (e.g., some cells in the eyes and bones) mature and differentiate into a state in 5) which they have a specialized function but do not divide or progress through the cell cycle. These cells are “stuck” in which stage?<br></br>A) G0 B) S C) G1 D) M phase E) G2

Answer 5

Answer: A

Question 6

6) During mitotic cell division, if chromosomal material is improperly divided between the two 6) daughter cells, one cell could receive three copies of a chromosome, and the other cell could receive only one. This is likely due to a defect in which process?<br></br>A) crossing over B) cytokinesis<br></br>C) homologous recombination<br></br>D) karyokinesis E) synapsis

Answer 6

Answer: D

Question 7

7) A eukaryotic cell is diploid and contains 6 chromosomes during G1 phase. If the cell undergoes 7) mitosis, how many daughter cells would be produced, and how many chromosomes would each one contain?<br></br>A) 2 daughter cells with 12 chromosomes each<br></br> <br></br>B) 2 daughter cells with 3 chromosomes each<br></br>C) 4 daughter cells with 12 chromosomes each<br></br>D) 2 daughter cells with 6 chromosomes each<br></br>E) 4 daughter cells with 6 chromosomes each

Answer 7

Answer: D

Question 8

8) During prophase of mitosis, a diploid cell with 2 nuclear chromosomes has how many sister 8) chromatids and how many contiguous DNA molecules?<br></br>A) 4 sister chromatids and 4 DNA molecules<br></br> <br></br>B) 4 sister chromatids and 2 DNA molecules<br></br>C) 2 sister chromatids and 2 DNA molecules<br></br>D) 8 sister chromatids and 4 DNA molecules<br></br>E) 2 sister chromatids and 4 DNA molecules

Answer 8

Answer: A

Question 9

9) You discover a new species of snail, Biologica terificia, and find that its haploid number is 4 (n = 4). 9) The somatic cells of Biologica terificia are diploid. How many chromosomes are in a somatic cell of the snail in G1 phase?<br></br>A) 4 B) 16<br></br> <br></br>C) 8 D) too many to count

Answer 9

Answer: C

Question 10

10) What is the role of the centromere during cell division?<br></br>A) Attach one sister chromatid to another sister chromatid.<br></br>B) Hold together the DNA of a single chromatid.<br></br>C) Attach two chromosomes to each other.<br></br>D) Serve as the initiation site for DNA synthesis.

Answer 10

Answer: A

Question 11

11) A single chromosome at metaphase contains how many DNA molecules? 11)<br></br>A) two<br></br>B) four<br></br> <br></br>C) one<br></br>D) more than four<br></br>E) impossible to determine

Answer 11

Answer: A

Question 12

12) Which organelle migrates during M phase to form the two opposite poles of the dividing cell and 12) acts as the source of the spindle fiber microtubules?<br></br>A) centrosome<br></br>B) chromosome<br></br>C) chiasmata<br></br>D) kinetochore <br></br>E) E) centromere

Answer 12

Answer: A

Question 13

14) The separation of sister chromatids during anaphase I of mitosis is known as chromosome 14) ________.<br></br>A) disjunction<br></br>B) cytokinesis<br></br>C) synapsis<br></br>D) crossing over E) karyokinesis

Answer 13

Answer: A

Question 14

15) A dihybrid has the genotype AaBb. After a normal mitotic division into two daughters cells, one 15) daughter cell will have the genotype ________ and the other will have the genotype ________.<br></br>A) Ab; aB<br></br>B) Aa; Bb<br></br>C) AaBb; AaBb<br></br>D) AABB; aabb<br></br>E) AB; ab

Answer 14

Answer: C

Question 15

16) Tumor suppressors are genes whose protein products regulate cell cycle checkpoints and ________. 16) A) promote advancement of the cell cycle B) activate proto- oncogenes<br></br>C) block progression of the cell cycle<br></br>D) prevent apoptosis in normal cells<br></br>E) phosphorylate proteins involved in the cell cycle

Answer 15

Answer: C

Question 16

17) Vinblastine is a commonly used chemotherapy drug that acts by interfering with the assembly of 17) microtubules. How does it likely target cancer cells?<br></br>A) by inhibiting DNA synthesis<br></br>B) by disrupting mitotic spindle formation C) by inhibiting protein kinases<br></br>D) by denaturing myosin and preventing the cleavage furrow from forming E) by suppressing cyclins

Answer 16

Answer: B

Question 17

18) Why might a parent cell undergo mitosis in a multi- cellular tissue? 18)<br></br>A) Cyclins are not phosphorylated.<br></br>B) Parent cell needs to replace nearby cells that have performed apoptosis.<br></br>C) Parent cell is damaged and needs to perform apoptosis.<br></br>D) Growth factor concentrations are low.<br></br>E) Parent cell needs to out- compete other cells around it for resources.

Answer 17

Answer: B

Question 18

19) If a cell begins to divide rapidly (as often seen in wound repair), what would you expect to happen 19) to the timing of G1 phase?<br></br>A) It would require less time than other cells.<br></br> <br></br>B) It would require more time than other cells.<br></br>C) The time it would require would depend on what other cells in the vicinity are doing.<br></br>D) It would require the same amount of time as any other cell.<br></br>E) It is not possible to say what would happen to the timing of G1 phase.

Answer 18

Answer: A

Question 19

20) The five substages of M phase are designed to accomplish two main goals: equal partitioning 20) between the two cells of chromosomal material and of cytoplasmic contents. What are these two processes called?<br></br>A) Depolymerization and Disjunction<br></br> <br></br>B) Karyokinesis and Cytokinesis<br></br>C) Nondisjunction and Centrosomes D) Kinetochore and Cohesion<br></br>E) There are not specific names for these process and are best described as in the question.

Answer 19

Answer: B

Question 20

21) During prometaphase, microtubules grow from the ________ to attach to the ________. 21)<br></br>A) Nucleolus; Chromosomes<br></br>B) Centrioles; Organelles<br></br> <br></br>C) Metaphase plate; Daughter chromosomes<br></br>D) Centrosomes; Kinetochores<br></br>E) E) Spindle; Chromatids

Answer 20

Answer: D

Question 21

22) Why are chromosomes more easily visible under a microscope during Metaphase as compared to 22) G2 phase?<br></br>A) They become stained by natural pigments in the cell.<br></br>B) They are highly condensed in Metaphase.<br></br>C) There is twice as much DNA during Metaphase than during G2 phase.<br></br>D) Chromosomes are contained in the nucleus during G2 but not during metaphase.<br></br>E) Proteins that bind chromosomes during Metaphase are highly visible.

Answer 21

Answer: B

Question 22

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.<br></br>23) When cyclin D1 is expressed in normal levels, it stimulates the cell cycle by promoting 23) transition from one cell cycle phase to another. If overexpressed, it can promote cancer by allowing cells to overproliferate. The normal cyclin D1 gene regulates which general cell cycle process?

Answer 22

Answer: cell cycle checkpoints<br></br> <br></br>MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.<br></br>24) During meiosis I, when does homologous chromosome pairing and recombination occur? 24) A) prophase I<br></br>B) metaphase I<br></br>C) pro- metaphase I<br></br>D) telophase I<br></br>E) anaphase I<br></br>»Answer: A<br></br>25) The binding of nonsister chromatids by a synaptonemal complex draws the homologs into close 25) contact so that what process can occur?<br></br>A) synapsis<br></br>B) karyokinesis C) disjunction<br></br>D) independent assortment<br></br>E) cytokinesis<br></br>»Answer: A

Question 23

26) Contact points between nonsister chromatids that mark the locations of DNA- strand exchange are 26) called ________.<br></br>A) metaphase plates B) chiasmata<br></br>C) synaptonemal complexes<br></br>D) kinetochores E) centrosomes

Answer 23

Answer: B

Question 24

27) Genes A and B are on different chromosomes. A dihybrid with the genotype AaBb undergoes 27) meiosis. Which of the following depicts a possible genotype in a gamete?<br></br> A) A B) B C) Bb D) AaBb E) AB F) Aa

Answer 24

Answer: E

Question 25

28) WT yeast (TRP+) can synthesize the amino acid tryptophan and can grow on media plates lacking 28) tryptophan. In contrast, mutant alleles (trpƺ) block tryptophan synthesis and result in an inability of<br></br> <br></br>mutant strains to grow on media lacking tryptophan. A diploid yeast was made through the cross M ADE+ × MAT΅ adeƺ. Meiosis was induced in the diploid strain to produce an ascus with four haploid spores, which were separated and grown on plates lacking tryptophan. How many spores are expec grow into colonies on the plate?<br></br> A) 0 B) 3 C) 4 D) 1 E) 2

Answer 25

Answer: E

Question 26

32) Why might a cell undergo meiosis rather than mitosis?<br></br>A) Diploid gametes are effective for asexual reproduction.<br></br>B) Haploid gametes can be genetically diverse.<br></br>C) Meiosis protects against mutations during reproduction.<br></br>D) It is more efficient to perform meiosis than mitosis.<br></br>E) Cells that perform meiosis can out- compete cells that perform mitosis.

Answer 26

Answer: B

Question 27

33) While female and male beetles both contain twenty diploid chromosomes, males have one smaller chromosome than in females. What can be inferred from this observation? A) Males require fewer genes than females.<br></br>B) Crossing over occurs between homologous chromosomes.<br></br>C) Biological sex is determined by the presence of an X or Y chromosome.<br></br>D) The number of autosomal chromosomes varies between gametes.<br></br>E) Chromosomes assort independently to determine biological sex.

Answer 27

Answer: C

Question 28

34) Crossing white- eyed male Drosophila to red- eyed females produces all red- eyed F1 offspring, but 34) the one half of the males in the F2 generation are white- eyed. What concept best explains this observation of eye color?<br></br>A) X- linked inheritance<br></br>B) autosomal dominance<br></br>C) independent assortment<br></br>D) random mutation<br></br>E) crossing over

Answer 28

Answer: A

Question 29

35) Biological sex in some species, such as Drosophila, is determined by genes present on both the ________.<br></br>A) nuclear and mitochondrial DNA<br></br>B) haploid and diploid chromosomes C) stem and gonad cells<br></br>D) prophase and Telophase chromosomes E) autosomal and sex chromosomes

Answer 29

Answer: E

Question 30

36) Chromosomal nondisjunction of the X chromosome in female gametes of humans means that live offspring can include ________.<br></br>A) females with XX, and males with XY or XO<br></br>B) females with XX or XXX, and males with XY or XXY <br></br>C) females with XX or XXX, and males with XY or XO<br></br>D) females with XX or XO, and males with XY or OY E) females with XX, and males with XY

Answer 30

Answer: B

Question 31

37) The biological sex of birds and some other mammals can be explained by females containing ________ chromosomes and males containing ________ chromosomes.<br></br>A) XY; XX B) XX; XY C) X; Y D) Z; W E) ZW; ZZ

Answer 31

Answer: D

Question 32

38) If a trait is X- linked recessive, who would express the trait?<br></br>A) females homozygous for the recessive allele and males hemizygous for the recessive allele<br></br>B) females homozygous for the dominant allele and males hemizygous for the recessive allele <br></br>C) the same proportions of females and males<br></br>D) females homozygous for the recessive allele and males hemizygous for the dominant allele <br></br>E) heterozygous females and males hemizygous for the dominant allele

Answer 32

Answer: A

Question 33

B) females homozygous for the dominant allele and males hemizygous for the recessive allele<br></br>C) females homozygous for the recessive allele and males hemizygous for the dominant allele<br></br>D) females homozygous for the recessive allele and males hemizygous for the recessive allele <br></br>E) heterozygous females and males hemizygous for the dominant allele

Answer 33

A»nswer: E

Question 34

40) Red- green color blindness is an X- linked recessive disorder. A woman with normal vision whose father was colorblind has children with a man with normal color vision. What is the probability that their first child will be colorblind?<br></br> A) 3/4 B) 1/4 C) 1 D) 1/2 E) 0

Answer 34

Answer: B

Question 35

41) Which dosage compensation mechanism is employed by female placental mammals?<br></br>A) X- inactivation<br></br>B) X chromosome crossing over<br></br>C) synteny<br></br>D) X nondisjunction E) Y- inactivation

Answer 35

Answer: A