AP Bio Chapter 12 review

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

B) prophase

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

A) 10

Density-dependent inhibition is explained by which of the following? A) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. B) 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. C) As cells become more numerous, more and more of them enter the S phase of the cell cycle. D) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism. E) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors.

A) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.

Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active? A) Cdk B) protein kinase C) MPF D) PDGF E) cyclin

A) Cdk

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

A) Cell division would allow for the orderly and efficient segregation of multiple linear chromosomes.

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

A) Cohesin must be cleaved enzymatically.

You have a series of cells, all of which were derived from tumors, and you first need to find out which ones are malignant. What could you do? A) Karyotype samples to look for unusual size and number of chromosomes. B) Measure metastasis. C) Time their cell cycles. D) See which ones are not overproliferating. E) Find out which ones have a higher rate of apoptosis.

A) Karyotype samples to look for unusual size and number of chromosomes.

A research team began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away? A) The cells show characteristics of tumors. B) They have altered series of cell cycle phases. C) The cells are unable to form spindle microtubules. D) They were originally derived from an elderly organism. E) The cells originated in the nervous system.

A) The cells show characteristics of tumors.

Why do neurons and some other specialized cells divide infrequently? A) They have been shunted into G0. B) They can no longer bind Cdk to cyclin. C) They no longer have active nuclei. D) They no longer carry receptors for signal molecules. E) They show a drop in MPF concentration.

A) They have been shunted into G0.

A student is looking through his light microscope (~450 X) at a squashed and stained onion root tip. Some, but not all, of the cells have clearly visible chromosome strands. Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely A) a plant cell in the process of cytokinesis. B) an animal cell in the process of cytokinesis. C) a plant cell in metaphase. D) an animal cell in the S phase of the cell cycle. E) a bacterial cell dividing.

A) a plant cell in the process of cytokinesis.

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

A) chromatids remain attached to one another until anaphase.

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) cyclin B) MPF C) Cdk D) PDGF E) protein kinase

A) cyclin

Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor? A) lack of appropriate cell death B) changes in the order of cell cycle stages C) metastasis D) inability of chromosomes to meet at the metaphase plate E) inability to form spindles

A) lack of appropriate cell death

Why do chromosomes coil during mitosis? A) to allow the chromosomes to move without becoming entangled and breaking B) to increase their potential energy C) to provide for the structure of the centromere D) to allow the sister chromatids to remain attached E) to allow the chromosomes to fit within the nuclear envelope

A) to allow the chromosomes to move without becoming entangled and breaking

The lettered circle in Figure 12.1 shows a diploid nucleus with four chromosomes. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is symbolized as black and the other haploid set is gray. The chromosomes in the unlettered circle have not yet replicated. Choose the correct chromosomal conditions for the following stages. What is the correct chromosomal condition at the prometaphase of mitosis? A) A B) B C) C D) D

B

Which of the following describe(s) cyclin-dependent kinase (Cdk)? A) Cdk is an enzyme that attaches phosphate groups to other proteins. B) Cdk is present throughout the cell cycle and is an enzyme that attaches phosphate groups to other proteins. C) Cdk is inactive, or "turned off," in the presence of cyclin. D) Cdk is inactive, or "turned off," in the presence of cyclin and it is present throughout the cell cycle. E) Cdk is present throughout the cell cycle.

B) Cdk is present throughout the cell cycle and is an enzyme that attaches phosphate groups to other proteins.

After which checkpoint is the cell first committed to continue the cell cycle through M? A) G0 B) G1 C) G2 D) previous M E) S

B) G1

Which of the following most accurately describes a cyclin? A) It is present in similar concentrations throughout the cell cycle. B) It activates a Cdk molecule when it is in sufficient concentration. C) It activates a Cdk when its concentration is decreased. D) It decreases in concentration when MPF activity increases. E) It is activated to phosphorylate by complexing with a Cdk.

B) It activates a Cdk molecule when it is in sufficient concentration.

For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable? A) It only attacks cells that are density dependent. B) It interferes with rapidly dividing cells. C) It interferes with cells entering G0. D) It is safe enough to limit all apoptosis. E) It does not alter metabolically active cells.

B) It interferes with rapidly dividing cells.

The cyclin component of MPF is destroyed toward the end of which phase? A) G0 B) M C) G1 D) S E) G2

B) M

A particular cyclin called cyclin E forms a complex with Cdk 2 (cyclin-dependent kinase 2). This complex is important for the progression of the cell from G1 into the S phase of the cell cycle. Which of the following statements is correct? A) The amount of free Cdk 2 is greatest during G1. B) The amount of free cyclin E is highest during G1. C) The amount of free Cdk 2 is greater during G1 compared to the S phase. D) The activity of the cyclin E/Cdk 2 complex is highest during G2. E) The amount of free cyclin E is greatest during the S phase.

B) The amount of free cyclin E is highest during G1.

All cell cycle checkpoints are similar in which way? A) They each have only one cyclin/Cdk complex. B) They activate or inactivate other proteins. C) They utilize the same Cdks. D) They respond to the same cyclins. E) They give the go-ahead signal to progress to the next checkpoint.

B) They activate or inactivate other proteins.

Several organisms, primarily protists, have what are called intermediate mitotic organization. These protists are intermediate in what sense? A) They use mitotic division but only have circular chromosomes. B) They maintain a nuclear envelope during division. C) They reproduce by binary fission in their early stages of development and by mitosis when they are mature. D) They never coil up their chromosomes when they are dividing. E) None of them form spindles.

B) They maintain a nuclear envelope during division.

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

B) a groove in the plasma membrane between daughter nuclei

In the cells of some organisms, mitosis occurs without cytokinesis. This will result in A) cell cycles lacking an S phase. B) cells with more than one nucleus. C) cells that are unusually small. D) destruction of chromosomes. E) cells lacking nuclei.

B) cells with more than one nucleus.

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

B) centrosome

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B? A) spindle attachment to kinetochores B) cleavage furrow formation and cytokinesis C) DNA synthesis D) cell elongation during anaphase E) spindle formation

B) cleavage furrow formation and cytokinesis

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. Once they had determined which cells were dividing, the team wanted to use a non-radioactive method to track whether various physiological factors (such as food or body temperature) affect the action of the pathogen. Which of the following would be effective, simple, and safe? A) counting newly formed plasma membranes B) counting the frequency of cells in mitosis C) measuring picograms of DNA D) measuring numbers of chromosomes E) measuring numbers of chromatids

B) counting the frequency of cells in mitosis

What explains anchorage dependence of animal cells in vitro or in vivo? A) the binding of cell-surface phospholipids to those of adjoining cells B) response of the plasma membrane to cell cycle controls C) the makeup of the extracellular matrix of the substrate D) the binding of cell-surface phospholipids to the substrate E) attachment of spindle fibers to centrioles

B) response of the plasma membrane to cell cycle controls

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

B) telophase

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) two chromosomes, each with six chromatids B) two long strands of DNA plus proteins C) one-twelfth of the genes of the organism D) two chromatids attached together at a centromere E) a single circular piece of DNA

B) two long strands of DNA plus proteins

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

C) 10

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) prophase. B) G2. C) G1. D) anaphase. E) metaphase.

C) G1.

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) M B) G0 C) G2 D) G1 E) S

C) G2

Which of the following triggers the cell's passage past the G2 checkpoint into mitosis? A) PDGF B) Cdk C) MPF D) protein kinase E) cyclin

C) MPF

If the cell whose nuclear material is shown in Figure 12.2 continues toward completion of mitosis, which of the following events would occur next? A) spindle fiber formation B) synthesis of chromatids C) formation of telophase nuclei D) cell membrane synthesis E) nuclear envelope breakdown

C) formation of telophase nuclei

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

C) how to use a hypotonic solution to swell nuclei

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

C) maintaining the region of overlap of microtubules in the cell's center

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

C) prevents shortening of microtubules.

The decline of MPF activity at the end of mitosis is due to A) the accumulation of cyclin. B) synthesis of DNA. C) the degradation of cyclin. D) the destruction of the protein kinase Cdk. E) decreased synthesis of Cdk.

C) the degradation of cyclin.

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

C) the formation of the mitotic spindle.

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

D) Golgi-derived vesicles

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

D) 32

Which of the following is released by platelets in the vicinity of an injury? A) protein kinase B) MPF C) Cdk D) PDGF E) cyclin

D) PDGF

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

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.

Which of the following is true concerning cancer cells? A) When they stop dividing, they do so at random points in the cell cycle. B) When they stop dividing, they do so at random points in the cell cycle, and they are not subject to cell cycle controls. C) They are not subject to cell cycle controls. D) When they stop dividing, they do so at random points in the cell cycle; they are not subject to cell cycle controls; and they do not exhibit density-dependent inhibition when growing in culture. E) They do not exhibit density-dependent inhibition when growing in culture.

D) When they stop dividing, they do so at random points in the cell cycle; they are not subject to cell cycle controls; and they do not exhibit density-dependent inhibition when growing in culture.

A student is looking through his light microscope (~450 X) at a squashed and stained onion root tip. Some, but not all, of the cells have clearly visible chromosome strands. When a cell is in anaphase of mitosis, which of the following will he see? A) formation of vesicles at the midline B) individual chromatids separating C) chromosomes clustered tightly at the center D) a clear area in the center of the cell E) chromosomes clustered at the poles

D) a clear area in the center of the cell

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

D) actin and tubulin

One difference between cancer cells and normal cells is that cancer cells A) are always in the M phase of the cell cycle. B) cannot function properly because they are affected by density-dependent inhibition. C) are arrested at the S phase of the cell cycle. D) continue to divide even when they are tightly packed together. E) are unable to synthesize DNA.

D) continue to divide even when they are tightly packed together.

Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called A) proton pumps. B) ATPases. C) kinetochores. D) cyclins. E) kinases.

D) cyclins.

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. 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) their tissue culture methods needed to be relearned. B) the presence of the pathogen made the experiment too contaminated to trust the results. C) infection causes lymphocyte cultures to skip some parts of the cell cycle. D) infection causes lymphocytes to divide more rapidly. E) infection causes cell cultures in general to reproduce more rapidly.

D) infection causes lymphocytes to divide more rapidly.

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

D) its destruction by a process initiated by the activity of its complex with a cyclin

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 cell walls B) chlorophyll and cell walls C) cell wall components and DNA D) organelle density and enzymatic activity E) chlorophyll and DNA

D) organelle density and enzymatic activity

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) labeled kinetochore proteins D) radioactive-labeled nucleotides E) spectrophotometry

D) radioactive-labeled nucleotides

Which of the following does not occur during mitosis? A) separation of sister chromatids B) spindle formation C) separation of the spindle poles D) replication of the DNA E) condensation of the chromosomes

D) replication of the DNA

The research team established similar lymphocyte cultures from a number of human donors, including healthy teenagers of both genders, patients already suffering from long-term bacterial infections, and elderly volunteers. They found that the increase in lymphocyte incorporation after pathogen introduction was slightly lower in some of the female teenagers and significantly lower in each of the elderly persons. They repeated the study with a larger number of samples but got the same results. Which of the following investigations might be most productive to show what the data on the teenagers might indicate? A) test teenagers who say they are not sexually active B) test teenagers from different school systems C) test male teenagers D) test relatives of the teens previously tested E) test female teens at different times in their menstrual cycles

D) test relatives of the teens previously tested

A student is looking through his light microscope (~450 X) at a squashed and stained onion root tip. Some, but not all, of the cells have clearly visible chromosome strands. When the cell has just completed telophase, which of the following does he see? A) individual chromatids separating B) formation of vesicles at the midline C) a clear area in the center of the cell D) two small cells with chromatin E) chromosomes clustered at the poles

D) two small cells with chromatin

53) What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis? A) A B) B C) C D) D E) E

E

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; 16 B) 8; 8 C) 16; 8 D) 12; 16 E) 16; 16

E) 16; 16

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) an MTOC (microtubule organizing center) B) synthesis of cohesin C) intact centromeres D) a kinetochore attached to the metaphase plate E) ATP as an energy source

E) ATP as an energy source

Cells from an advanced malignant tumor most often have very abnormal chromosomes, and often an abnormal total number of chromosomes. Why might this occur? A) Chromosomally abnormal cells still have normal metabolism. B) Transformation introduces new chromosomes into cells. C) Cancer cells are no longer density dependent. D) Cancer cells are no longer anchorage dependent. E) Chromosomally abnormal cells can still go through cell cycle checkpoints.

E) Chromosomally abnormal cells can still go through cell cycle checkpoints.

At the M phase checkpoint, the complex allows for what to occur? A) Cohesins alter separase to allow chromatids to separate. B) Daughter cells are allowed to pass into G1. C) Kinetochores are able to bind to spindle microtubules. D) All microtubules are made to bind to kinetochores. E) Separase enzyme cleaves cohesins and allows chromatids to separate.

E) Separase enzyme cleaves cohesins and allows chromatids to separate.

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 never leave metaphase. B) The cell would prematurely enter anaphase. C) The cell would never enter prophase. D) The cell would never enter metaphase. E) The cell would undergo normal mitosis, but fail to enter the next G1 phase.

E) The cell would undergo normal mitosis, but fail to enter the next G1 phase.

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) Each resultant daughter cell would also be unable to form a spindle. B) The chromosomes would segregate but in a disorderly pattern. C) The cells would immediately die. D) The cells would be unable to begin M and stay in G2. E) The chromosomes would coil and shorten but have no spindle to which to attach.

E) The chromosomes would coil and shorten but have no spindle to which to attach.

The research team established similar lymphocyte cultures from a number of human donors, including healthy teenagers of both genders, patients already suffering from long-term bacterial infections, and elderly volunteers. They found that the increase in lymphocyte incorporation after pathogen introduction was slightly lower in some of the female teenagers and significantly lower in each of the elderly persons. They repeated the study with a larger number of samples but got the same results. What might be among the research team's conclusions? A) The patient samples should have had the lowest response but did not, so the experiment is invalid. B) The young men had higher responses because they are generally healthier. C) The young women showed these results because they have poorer nutrition. D) The elderly donor samples represent cells no longer capable of any cell division. E) The elderly persons' samples demonstrated their lowered immune responses.

E) The elderly persons' samples demonstrated their lowered immune responses.

Several organisms, primarily protists, have what are called intermediate mitotic organization. What is the most probable hypothesis about these intermediate forms of cell division? A) They rely on totally different proteins for the processes they undergo. B) They represent a form of cell reproduction which must have evolved completely separately from those of other organisms. C) They may be more closely related to plant forms that also have unusual mitosis. D) They demonstrate that these species are not closely related to any of the other protists and may well be a different kingdom. E) They show some but not all of the evolutionary steps toward complete mitosis.

E) They show some but not all of the evolutionary steps toward complete mitosis.

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. Which of the following questions might be answered by such a method? A) How many cells are produced by the culture per hour? B) When is the S chromosome synthesized? C) When do spindle fibers attach to chromosomes? D) How many picograms of DNA are made per cell cycle? E) What is the length of the S phase of the cell cycle?

E) What is the length of the S phase of the cell cycle?

The MPF protein complex turns itself off by A) activating the anaphase-promoting complex. B) activating an enzyme that stimulates cyclin. C) binding to chromatin. D) exiting the cell. E) activating a process that destroys cyclin components.

E) activating a process that destroys cyclin components.

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

E) dinoflagellates and diatoms only

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to A) inhibition of DNA synthesis. B) myosin denaturation and inhibition of cleavage furrow formation. C) suppression of cyclin production. D) inhibition of regulatory protein phosphorylation. E) disruption of mitotic spindle formation.

E) disruption of mitotic spindle formation.

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. Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that A) gamma contains 48 times more DNA and RNA than beta. B) beta cells reproduce asexually. C) beta and gamma contain the same amount of DNA. D) beta is a plant cell and gamma is an animal cell. E) gamma contains more DNA than beta.

E) gamma contains more DNA than beta.

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) interphase C) prophase D) telophase E) metaphase

E) metaphase

G1 is represented by which numbered part(s) of the cycle? A) I or V B) II or IV C) III only D) IV only E) V only

I or V

Which number represents DNA synthesis? A) I B) II C) III D) IV E) V

II

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

II

MPF reaches its threshold concentration at the end of this stage. A) I B) II C) III D) IV E) V

III

At which of the numbered regions would you expect to find cells at metaphase? A) I and IV B) II only C) III only D) IV only E) V only

III only

55) In the figure above, mitosis is represented by which numbered part(s) of the cycle? A) I B) II C) III D) IV E) V

IV