AP Biology Chapter 12 Review

Multiple Choice
Identify the choice that best completes the statement or answers the 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.

____	2.	What is a chromatid?
a. | a chromosome in  of the cell cycle
b. | a replicate chromosome
c. | a chromosome found outside the nucleus
d. | a special region that holds two centromeres together
e. | another name for the chromosomes found in genetics

____	3.	If there are 20 chromatids in a cell, how many centromeres are there?
a. | 10
b. | 20
c. | 30
d. | 40
e. | 80

____	4.	How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in  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.

____	5.	Which term describes centrioles beginning to move apart in animal cells?
a. | telophase
b. | anaphase
c. | prometaphase
d. | metaphase
e. | prophase

____	6.	Which is the longest of the mitotic stages?
a. | telophase
b. | anaphase
c. | prometaphase
d. | metaphase
e. | prophase

____	7.	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

____	8.	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

____	9.	A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes?
a. | 12
b. | 16
c. | 23
d. | 46
e. | 92

____	10.	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

____	11.	If there are 20 chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
a. | 10
b. | 20
c. | 30
d. | 40
e. | 80

Use the data in Table 12.1 to answer the following questions.

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.

Table 12.1: Minutes Spent in Cell Cycle Phases

____	12.	The best conclusion concerning delta is that the cells
a. | contain no DNA.
b. | contain no RNA.
c. | contain only one chromosome that is very short.
d. | are actually in the  phase.
e. | divide in the  phase.

____	13.	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

____	14.	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

____	15.	Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with
a. | a single large nucleus.
b. | high concentrations of actin and myosin.
c. | two abnormally small nuclei.
d. | two nuclei.
e. | two nuclei but with half the amount of DNA.

____	16.	Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants
a. | the spindles contain microfibrils in addition to microtubules, whereas animal spindles do not contain microfibrils.
b. | sister chromatids are identical, but they differ from one another in animals.
c. | a cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage.
d. | chromosomes become attached to the spindle at prophase, whereas in animals chromosomes do not become attached until anaphase.
e. | spindle poles contain centrioles, whereas spindle poles in animals do not.

____	17.	The formation of a cell plate is beginning across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?
a. | an animal cell in metaphase
b. | an animal cell in telophase
c. | an animal cell undergoing cytokinesis
d. | a plant cell in metaphase
e. | a plant cell undergoing cytokinesis

____	18.	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.

____	19.	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

____	20.	Chromosomes first become visible during which phase of mitosis?
a. | prometaphase
b. | telophase
c. | prophase
d. | metaphase
e. | anaphase

____	21.	During which phases of mitosis are chromosomes composed of two chromatids?
a. | from interphase through anaphase
b. | from  of interphase through metaphase
c. | from metaphase through telophase
d. | from anaphase through telophase
e. | from  of interphase through metaphase

____	22.	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 was the nucleus with 6 picograms of DNA?
a. |
b. |
c. | S
d. |
e. | M

____	23.	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. Those cells would have ____ picograms at the end of the S phase and ____ picograms at the end of G_2.
a. | 8; 8
b. | 8; 16
c. | 16; 8
d. | 16; 16
e. | 12; 16

____	24.	Imagine looking through a microscope at a squashed onion root tip. The chromosomes of many of the cells are plainly visible. In some cells, replicated chromosomes are aligned along the center (equator) of the cell. These particular cells are in which stage of mitosis?
a. | telophase
b. | prophase
c. | anaphase
d. | metaphase
e. | prometaphase

____	25.	In order 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.

____	26.	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

The following applies to the questions below.

Several organisms, primarily Protists, have what are called intermediate mitotic organization.

____	27.	What is the most probable hypothesis about these intermediate forms of cell division?
a. | They represent a form of cell reproduction which must have evolved completely separately from those of other organisms.
b. | They demonstrate that these species are not closely related to any of the other Protists and may well be a different Kingdom.
c. | They rely on totally different proteins for the processes they undergo.
d. | They may be more closely related to plant forms that also have unusual mitosis.
e. | They show some of the evolutionary steps toward complete mitosis but not all.

____	28.	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. | Non-kinetochore spindle fibers serve to push chromosomes in the direction of the poles.
d. | both A and B
e. | A, B, and C

____	29.	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 fibers in the cell's center
e. | pulling the poles of the spindles closer to one another

Use the following to answer the questions below.

Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student-faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times.

____	30.	The research team used the setup to study the incorporation of labeled nucleotides into a culture of lymphocytes and found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. They concluded that
a. | the presence of the pathogen made the experiment too contaminated to trust the results.
b. | their tissue culture methods needed to be relearned.
c. | infection causes lymphocytes to divide more rapidly.
d. | infection causes cell cultures in general to reproduce more rapidly.
e. | infection causes lymphocyte cultures to skip some parts of the cell cycle.

____	31.	Which of the following is released by platelets in the vicinity of an injury?
a. | PDGF
b. | MPF
c. | protein kinase
d. | cyclin
e. | Cdk

____	32.	Which is a general term for enzymes that activate or inactivate other proteins by phosphorylating them?
a. | PDGF
b. | MPF
c. | protein kinase
d. | cyclin
e. | Cdk

____	33.	Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?
a. | PDGF
b. | MPF
c. | protein kinase
d. | cyclin
e. | Cdk

____	34.	Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active?
a. | PDGF
b. | MPF
c. | protein kinase
d. | cyclin
e. | Cdk

____	35.	This is the shortest part of the cell cycle:
a. |
b. |
c. | S
d. |
e. | M

____	36.	DNA is replicated at this time of the cell cycle:
a. |
b. |
c. | S
d. |
e. | M

____	37.	The cyclin component of MPF is destroyed toward the end of this phase:
a. |
b. |
c. | S
d. |
e. | M

The following questions are based on Figure 12.3.

Figure 12.3

____	38.	In the figure above, mitosis is represented by which number?
a. | I
b. | II
c. | III
d. | IV
e. | V

____	39.	Which number represents DNA synthesis?
a. | I
b. | II
c. | III
d. | IV
e. | V

____	40.	Which number represents the point in the cell cycle during which the chromosomes are replicated?
a. | I
b. | II
c. | III
d. | IV
e. | V

____	41.	MPF reaches its threshold concentration at the end of this stage.
a. | I
b. | II
c. | III
d. | IV
e. | V

____	42.	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  phase.

____	43.	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.
e. | As cells become more numerous, the level of waste products increases, eventually slowing down metabolism.

____	44.	Which of the following is true concerning cancer cells?
a. | They do not exhibit density-dependent inhibition when growing in culture.
b. | When they stop dividing, they do so at random points in the cell cycle.
c. | They are not subject to cell cycle controls.
d. | B and C only
e. | A, B, and C

____	45.	A particular cyclin called cyclin E forms a complex with a cyclin-dependent kinase called Cdk 2. This complex is important for the progression of the cell from  into the S phase of the cell cycle. Which of the following statements is correct?
a. | The amount of cyclin E is greatest during the S phase.
b. | The amount of Cdk 2 is greater during  compared to the S phase.
c. | The amount of cyclin E is highest during .
d. | The amount of Cdk 2 is greatest during .
e. | The activity of the cyclin E/Cdk 2 complex is highest during .

____	46.	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.
e. | a plant cell in metaphase.

____	47.	A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in
a. |
b. | .
c. | prophase.
d. | metaphase.
e. | anaphase.

____	48.	One difference between cancer cells and normal cells is that cancer cells
a. | are unable to synthesize DNA.
b. | are arrested at the S phase of the cell cycle.
c. | continue to divide even when they are tightly packed together.
d. | cannot function properly because they are affected by density-dependent inhibition.
e. | are always in the M phase of the cell cycle.

____	49.	In the cells of some organisms, mitosis occurs without cytokinesis. This will result in
a. | cells with more than one nucleus.
b. | cells that are unusually small.
c. | cells lacking nuclei.
d. | destruction of chromosomes.
e. | cell cycles lacking an S phase.

____	50.	Which of the following does not occur during mitosis?
a. | condensation of the chromosomes
b. | replication of the DNA
c. | separation of sister chromatids
d. | spindle formation
e. | separation of the spindle poles

AP Biology Chapter 12 Review
Answer Section

MULTIPLE CHOICE

	1.	ANS:	A	PTS:	1

	2.	ANS:	B	PTS:	1

	3.	ANS:	A	PTS:	1

	4.	ANS:	D	PTS:	1

	5.	ANS:	E	PTS:	1

	6.	ANS:	D	PTS:	1

	7.	ANS:	B	PTS:	1

	8.	ANS:	D	PTS:	1

	9.	ANS:	D	PTS:	1

	10.	ANS:	B	PTS:	1

	11.	ANS:	A	PTS:	1

	12.	ANS:	D	PTS:	1

	13.	ANS:	B	PTS:	1

	14.	ANS:	E	PTS:	1

	15.	ANS:	D	PTS:	1

	16.	ANS:	C	PTS:	1

	17.	ANS:	E	PTS:	1

	18.	ANS:	A	PTS:	1

	19.	ANS:	B	PTS:	1

	20.	ANS:	C	PTS:	1

	21.	ANS:	E	PTS:	1

	22.	ANS:	D	PTS:	1

	23.	ANS:	D	PTS:	1

	24.	ANS:	D	PTS:	1

	25.	ANS:	C	PTS:	1

	26.	ANS:	B	PTS:	1

	27.	ANS:	E	PTS:	1

	28.	ANS:	B	PTS:	1

	29.	ANS:	D	PTS:	1

	30.	ANS:	C	PTS:	1

	31.	ANS:	A	PTS:	1

	32.	ANS:	C	PTS:	1

	33.	ANS:	D	PTS:	1

	34.	ANS:	E	PTS:	1

	35.	ANS:	E	PTS:	1

	36.	ANS:	C	PTS:	1

	37.	ANS:	E	PTS:	1

	38.	ANS:	D	PTS:	1

	39.	ANS:	B	PTS:	1

	40.	ANS:	B	PTS:	1

	41.	ANS:	C	PTS:	1

	42.	ANS:	E	PTS:	1

	43.	ANS:	B	PTS:	1

	44.	ANS:	E	PTS:	1

	45.	ANS:	C	PTS:	1

	46.	ANS:	B	PTS:	1

	47.	ANS:	A	PTS:	1

	48.	ANS:	C	PTS:	1

	49.	ANS:	A	PTS:	1

	50.	ANS:	B	PTS:	1