Download Bio 102 Practice Problems Cell Cycle and Cell Division

Bio 102 Practice Problems
Cell Cycle and Cell Division
Multiple choice: Unless otherwise directed, circle the one best answer:
1. Which one of the following events does NOT occur during prophase of mitosis?
A.
B.
C.
D.
E.
Polymerization of tubulin into microtubules.
Attachment of kinetochore proteins to spindle fibers.
Pairing of homologous chromosomes.
Breakdown of nuclear membrane.
Wrapping of DNA strands around proteins to form a more compact structure.
2. During which phase of the cell cycle are leading strands synthesized?
A.
B.
C.
D.
E.
G1
S
G2
Prophase
Telophase
3. Which one of the following does not accurately describe the spindle?
A.
B.
C.
D.
E.
The spindle becomes attached to chromosomes at the centromere
The spindle attaches to chromosomes during prophase.
The spindle is made of many copies of a protein.
The spindle is present in Meiosis I, but not Meiosis II.
The spindle fibers shorten during anaphase.
4. During what process do eukaryotic cells become haploid?
A. Nondisjunction
B. S phase
C. Anaphase of mitosis
D. Meiosis I
E. Meiosis II
5. Sister chromatids are made during what part of the cell cycle?
A.
B.
C.
D.
E.
Prophase
G1
G2
S
Cytokinesis
Short answer (show your work or thinking to get partial credit):
1. Below are three dividing cells. Assuming that all three cells come from the same species, use the first blank
below each cell to tell whether this is mitosis, meiosis I, or meiosis II and the second blank to tell what stage
of mitosis or meiosis the cell is in.
2. The figure below shows three cells in the process of division. If no additional information is given, can you
tell what kind of division is occurring? Fill in the first blank under each cell with mitosis, meiosis I, or
meiosis II. If there is more than one possibility, list all of them. Then fill in the second blank to indicate the
stage (phase) of mitosis or meiosis that this cell is in.
3. Onions have 16 chromosomes. (A) Sketch an onion cell as it would look during metaphase of mitosis, and (B)
sketch an onion cell as it would look during anaphase I of meiosis. Label the appropriate cellular structures in
both drawings.
4. A pea plant is homozygous recessive for gene A and heterozygous for gene B. These two genes are located on
the same chromosome. It is also heterozygous for gene C, which is located on a separate chromosome. Make
two sketches to show the two ways this plant's chromosomes could be arranged during metaphase of
meiosis I. Be sure to show the genes and alleles.
5. The cells below come from the same organism and are in the process of cell divison:
A
B
C
D
a. What is N for this organism?
b. Circle the letter of each cell that could be either a germ cell or a gamete.
c. In the blank below each cell, place one of the following letters: I for Interphase, P for Prophase, M for
Metaphase, A for Anaphase or T for Telophase.
6. For fruit flies, N=4 and 2N=8.
a. Sketch a dividing fruit fly cell which is in prophase I.
b. Sketch a dividing fruit fly cell which is in metaphase of mitosis.
7. Genetic analysis of cancer cells shows that they are usually aneuploid (have more or fewer chromosomes than
normal). In addition to dividing rapidly, they also very often have mutations which affect the checkpoints of
the cell cycle. Suppose a cell acquires a mutation so that the checkpoint at the end of G2 is ignored. Explain
why the descendants of this cell would be very likely to become aneuploid.
8. For the following questions, assume you are working with a species where 2N = 2.
a. In the space below, draw a cell as it would appear in anaphase I.
b. Suppose the individual whose cell you drew is heterozygous for two genes, D and E, and that its mother is
homozygous recessive for both genes. Show the alleles of these two genes in your drawing.
c. Is it possible for this individual to produce a gamete with the genotype De? Explain.
9. In our sporulation lab, when a yeast cell successfully sporulated, one cell became four smaller spores, all of
which were contained within the ascus. Why were there four spores?
10. The amazing Dr. Johnston, yeast biologist extraordinaire, has discovered a new species of yeast that can grow
on high-quality chocolate bars. For this particular yeast species, N=3. Like the yeast we worked with in lab, if
there’s no chocolate available, a diploid cell can divide by meiosis to produce four haploid spores. In the
space below, draw: (A) A diploid yeast cell as it would appear under the microscope during S phase of the
cell cycle; (B) The same cell as it would appear during anaphase I; and (C) What one of the spores would look
like if we could see its chromosomes.
A
B
C
True or False? Read carefully: a question is false unless it is completely true!
T
T
T
T
T
T
T
□ □
F
□
□
□
□
□
□
F
F
F
F
F
F
□
□
□
□
□
□
T
□
□
□
□
□
T
□ □
T
T
T
T
F
F
F
F
F
□
□
□
□
□
F
T
□ □
□ □
T
□ □
T
1. Crossing-over is relatively infrequent between any two genes, but always occurs somewhere
during meiosis.
2. Sister chromatids have identical alleles.
3. Cells that divide by meiosis become haploid after the first division (meiosis I).
4. In humans, the only cells that can divide by meiosis would be found in the testes and ovaries).
5. Homologous pairs are produced when DNA replicates during S phase, prior to mitosis or meiosis.
6. For a human cell, N=23, meaning that cells that have completed meiosis I have 23 chromosomes.
7. Anaphase of mitosis and anaphase of meiosis II are similar in that sister chromatids separate from
each other.
8. After meiosis I, the two daughter cells are temporarily diploid.
9. A normal human cell has 46 chromosomes at every stage of meiosis.
10. Homologous chromosomes are paired only during prophase of meiosis I.
11. Homologous chromosomes have the same genes.
12. A cell that never divides, such as a nerve cell, is in the G1 phase of the cell cycle but can’t pass
through the checkpoint into G2.
13. At the end of meiosis I, the two daughter cells produced by a dividing germ cell are haploid and
genetically different.
F
14. A mutation would be inherited only if it occurs in the DNA of a germ cell.
F
15. At any given time, every cell in the human body would be in one of the four phases of the cell
cycle: G1, S, G2 or M.
F
16. Sister chromatids separate during anaphase of meiosis II.