Question 1

The centromere is a region in which A) chromatids remain attached to one another until anaphase. B) metaphase chromosomes become aligned at the metaphase plate. C) chromosomes are grouped during telophase. D) the nucleus is located prior to mitosis. E) new spindle microtubules form at either end.

Accepted Answer

A

Question 2

``` Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells? A) 4 B) 8 C) 16 D) 32 E) 64 ```

Accepted Answer

D

Question 3

``` If there are 20 chromatids in a cell, how many centromeres are there? A) 10 B) 20 C) 30 D) 40 E) 80 ```

Accepted Answer

A

Question 4

For a newly evolving protist, what would be the advantage of using eukaryote-like cell division rather than binary fission? A) Binary fission would not allow for the formation of new organisms. B) Cell division would allow for the orderly and efficient segregation of multiple linear chromosomes. C) Cell division would be faster than binary fission. D) Cell division allows for lower rates of error per chromosome replication. E) Binary fission would not allow the organism to have complex cells.

Accepted Answer

B

Question 5

Suppose a biologist can separate one of a dozen pieces of chromatin from a eukaryotic (animal) nucleus. It might consist of which of the following? A) one-twelfth of the genes of the organism B) two chromosomes, each with six chromatids C) a single circular piece of DNA D) two long strands of DNA plus proteins E) two chromatids attached together at a centromere

Accepted Answer

D

Question 6

At which phase are centrioles beginning to move apart in animal cells? ``` A) telophase B) anaphase C) prometaphase D) metaphase E) prophase ```

Accepted Answer

E

Question 7

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

Accepted Answer

D

Question 8

If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis? ``` A) 10 B) 20 C) 30 D) 40 E) 80 ```

Accepted Answer

A

Question 9

Where do the microtubules of the spindle originate during mitosis in both plant and animal cells? ``` A) centromere B) centrosome C) centriole D) chromatid E) kinetochore ```

Accepted Answer

B

Question 10

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 formation of the mitotic spindle. B) anaphase. C) formation of the centrioles. D) chromatid assembly. E) the S phase of the cell cycle. ```

Accepted Answer

A

Question 11

Which of the following are primarily responsible for cytokinesis in plant cells but not in animal cells? ``` A) kinetochores B) Golgi-derived vesicles C) actin and myosin D) centrioles and centromeres E) cyclin-dependent kinases ```

Accepted Answer

B

Question 12

In which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis? ``` A) seedless plants B) dinoflagellates C) diatoms D) dinoflagellates and diatoms only E) seedless plants, dinoflagellates, and diatoms ```

Accepted Answer

D

Question 13

Movement of the chromosomes during anaphase would be most affected by a drug that ``` A) reduces cyclin concentrations. B) increases cyclin concentrations. C) prevents elongation of microtubules. D) prevents shortening of microtubules. E) prevents attachment of the microtubules to the kinetochore. ```

Accepted Answer

D

Question 14

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA? ``` A) G₀ B) G₁ C) S D) G₂ E) M ```

Accepted Answer

D

Question 15

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G₂? ``` A) 8; 8 B) 8; 16 C) 16; 8 D) 16; 16 E) 12; 16 ```

Accepted Answer

D

Question 16

For anaphase to begin, which of the following must occur? A) Chromatids must lose their kinetochores. B) Cohesin must attach the sister chromatids to each other. C) Cohesin must be cleaved enzymatically. D) Kinetochores must attach to the metaphase plate. E) Spindle microtubules must begin to depolymerize.

Accepted Answer

C

Question 17

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 E) to provide for the structure of the centromere

Accepted Answer

B

Question 18

Which of the following best describes how chromosomes move toward the poles of the spindle during mitosis? A) The chromosomes are "reeled in" by the contraction of spindle microtubules. B) Motor proteins of the kinetochores move the chromosomes along the spindle microtubules. C) Nonkinetochore spindle fibers serve to push chromosomes in the direction of the poles. D) The chromosomes are "reeled in" by the contraction of spindle microtubules, and motor proteins of the kinetochores move the chromosomes along the spindle microtubules. E) The chromosomes are "reeled in" by the contraction of spindle microtubules, motor proteins of the kinetochores move the chromosomes along the spindle microtubules, and nonkinetochore spindle fibers serve to push chromosomes in the direction of the poles.

Accepted Answer

D

Question 19

Which of the following is a function of those spindle microtubules that do not attach to kinetochores? A) maintaining an appropriate spacing among the moving chromosomes B) producing a cleavage furrow when telophase is complete C) providing the ATP needed by the fibers attached to kinetochores D) maintaining the region of overlap of microtubules in the cell's center E) pulling the poles of the spindles closer to one another

Accepted Answer

D

Question 20

During which phase of mitosis do the chromatids become chromosomes? ``` A) telophase B) anaphase C) prophase D) metaphase E) cytokinesis ```

Accepted Answer

A

Question 21

Which of the following was a discovery that had to be made before human chromosomes could be correctly counted? A) how to use a hypotonic solution to swell nuclei B) how to visualize sperm nuclei C) how to visualize chromosomes D) when to see chromosomes separate from one another E) when to see chromosomes in pairs

Accepted Answer

A

Question 22

Which of the following is (are) required for motor proteins to function in the movement of chromosomes toward the poles of the mitotic spindle? A) intact centromeres B) an MTOC (microtubule organizing center) C) a kinetochore attached to the metaphase plate D) ATP as an energy source E) synthesis of cohesin

Accepted Answer

D

Question 23

What is a cleavage furrow? A) a ring of vesicles forming a cell plate B) the separation of divided prokaryotes C) a groove in the plasma membrane between daughter nuclei D) the metaphase plate where chromosomes attach to the spindle E) the space that is created between two chromatids during anaphase

Accepted Answer

C

Question 24

``` Which of the following proteins are involved in binary fission as well as eukaryotic mitotic division? A) cyclins B) Cdks C) MPF D) actin and tubulin E) cohesins ```

Accepted Answer

D

Question 25

Using which of the following techniques would enable your lab group to distinguish between a cell in G₂ and a cell from the same organism in G₁? ``` A) fluorescence microscopy B) electron microscopy C) spectrophotometry D) radioactive-labeled nucleotides E) labeled kinetochore proteins ```

Accepted Answer

D

Question 26

You have the technology necessary to measure each of the following in a sample of animal cells: chlorophylls, organelle density, picograms of DNA, cell wall components, and enzymatic activity. Which would you expect to increase significantly from M to G₁? ``` A) organelle density and enzymatic activity B) cell wall components and DNA C) chlorophyll and cell walls D) organelle density and cell walls E) chlorophyll and DNA ```

Accepted Answer

A

Question 27

A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of cells in G₂? A) The cells would immediately die. B) The cells would be unable to begin M and stay in G₂. C) The chromosomes would coil and shorten but have no spindle to which to attach. D) The chromosomes would segregate but in a disorderly pattern. E) Each resultant daughter cell would also be unable to form a spindle.

Accepted Answer

C

Question 28

What causes the decrease in the amount of cyclin at a specific point in the cell cycle? A) an increase in production once the restriction point is passed B) the cascade of increased production once its protein is phosphorylated by Cdk C) the changing ratio of cytoplasm to genome D) its destruction by a process initiated by the activity of its complex with a cyclin E) the binding of PDGF to receptors on the cell surface

Accepted Answer

D

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Chapter 12 Flashcards

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