Understanding Cell Division: AP Biology Mitosis And Meiosis Test
Prepare for the AP Biology Mitosis and Meiosis Test with our engaging quiz designed to test your understanding of cellular reproduction. This quiz will help you grasp the essential concepts, stages, and differences between mitosis and meiosis. With multiple-choice questions and detailed explanations, you can identify areas for improvement and reinforce your knowledge.
Additionally, this quiz serves as an excellent AP Biology Meiosis Practice Test, allowing you to focus specifically on the intricacies of meiosis, including gamete formation and genetic variation. Don't miss this opportunity to assess your readiness for the AP exam! Join now to enhance your study Read moreexperience and boost your confidence before the big test day.
AP Biology Meiosis Practice Questions and Answers
- 1.
The centromere is a region in which:
- A.
Chromatids are attached to one another.
- B.
Metaphase chromosomes become aligned.
- C.
Chromosomes are grouped during telophase.
- D.
The nucleus is located prior to mitosis.
- E.
New spindle microtubules form.
Correct Answer
A. Chromatids are attached to one another.Explanation
The centromere is a region in which chromatids are attached to one another. During cell division, each chromosome consists of two identical chromatids held together at the centromere. The centromere plays a crucial role in ensuring the proper separation of chromatids during mitosis or meiosis. It serves as an attachment site for spindle fibers, which help to pull the chromatids apart and distribute them equally to the daughter cells. Therefore, the correct answer is that the centromere is a region in which chromatids are attached to one another.Rate this question:
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- 2.
What is a chromatid?
- A.
A chromosome in G1 of the cell cycle
- B.
A replicated 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
Correct Answer
B. A replicated chromosomeExplanation
A chromatid is a replicated chromosome. During the S phase of the cell cycle, a chromosome is duplicated and consists of two identical sister chromatids held together by a centromere. Each chromatid contains a copy of the genetic information of the original chromosome. Therefore, the correct answer is a replicated chromosome.Rate this question:
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- 3.
What is the name for the special region on a duplicated chromosome that holds the sister chromatids together?
- A.
Centrosome
- B.
Centromere
- C.
Kinetochore
- D.
Desmosome
- E.
Microtubule organizer region
Correct Answer
B. CentromereExplanation
The centromere is the correct answer because it is the region on a duplicated chromosome that holds the sister chromatids together. It is responsible for ensuring that the replicated chromosomes are properly distributed to daughter cells during cell division. The centrosome is not directly involved in holding sister chromatids together, but rather plays a role in organizing microtubules. Kinetochore is a protein structure that forms on the centromere and attaches the chromatids to the spindle fibers. Desmosome is a type of cell junction, and microtubule organizer region refers to a specific region within a cell.Rate this question:
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- 4.
How many cells will be present after a zygote undergoes 5 mitotic cell divisions?
- A.
4
- B.
8
- C.
16
- D.
32
- E.
64
Correct Answer
D. 32Explanation
Each cell division doubles the number of cells. Starting with one cell (the fertilized egg), the first division produces 2 cells, the second division produces 4 cells, the third division produces 8 cells, the fourth division produces 16 cells, and the fifth division produces 32 cells. Therefore, after five cell divisions, the early embryo would have 32 cells.Rate this question:
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- 5.
If there are 20 chromatids in a cell, how many centromeres are there?
- A.
10
- B.
20
- C.
30
- D.
40
- E.
80
Correct Answer
A. 10Explanation
In the presence of 20 chromatids, they exist as identical pairs of two, denoting the occurrence of replication, and thus, comprising sister chromatids. Consequently, the total number of centromeres in this scenario would be 10.Rate this question:
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- 6.
Which of the following statements is not true?
- A.
Mitosis produces new nuclei with exactly the same chromosomal endowment as the parent nucleus.
- B.
Mitosis may occur without cytokinesis.
- C.
Mitosis and cytokinesis are required for asexual reproduction.
- D.
All cells come from a preexisting cell.
- E.
The mitotic spindles in prokaryotic cells are composed of microtubules.
Correct Answer
E. The mitotic spindles in prokaryotic cells are composed of microtubules.Explanation
Mitotic spindles are not present in prokaryotic cells. Prokaryotic cells undergo a process called binary fission, which does not involve the formation of mitotic spindles. Therefore, the statement that the mitotic spindles in prokaryotic cells are composed of microtubules is not true.Rate this question:
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- 7.
The lettered circle in the figure above 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 stage. *At prometaphase of mitosis
Correct Answer
B, bExplanation
At prometaphase of mitosis, the chromosomes have already replicated and are beginning to condense. The lettered circle in the figure shows a diploid nucleus with four chromosomes, two pairs of homologous chromosomes. One pair is long (symbolized as B) and the other pair is short (symbolized as b). The chromosomes in the unlettered circle have not yet replicated. Therefore, the correct chromosomal conditions for this stage are B, b.Rate this question:
- 8.
The lettered circle in the figure above 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 stage. one daughter nucleus at telophase of mitosis
Correct Answer
E - 9.
Which phase of mitosis is characterized by two centrosomes arranged at opposite poles of the cell?
- A.
Telophase
- B.
Anaphase
- C.
Prometaphase
- D.
Metaphase
- E.
Prophase
Correct Answer
C. PrometapHaseExplanation
The description states that two centrosomes are arranged at opposite poles of the cell. The phase of mitosis where this arrangement occurs is prometaphase. In prometaphase, the nuclear envelope breaks down, allowing the centrosomes to move to opposite ends of the cell and form the spindle apparatus. Therefore, the correct answer is C, prometaphase. The lowercase "c" is likely a typographical error and can be ignored.Rate this question:
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- 10.
During which phase of mitosis do centrioles begin to move apart in animal cells?
- A.
Telophase
- B.
Anaphase
- C.
Prometaphase
- D.
Metaphase
- E.
Prophase
Correct Answer
E. PropHaseExplanation
The correct answer is E, prophase. Prophase marks the beginning of mitosis and includes several important changes within the cell that set the stage for successful cell division. In animal cells, the centrioles—which are located near the nucleus—start to separate and move towards opposite poles of the cell, laying the groundwork for the mitotic spindle formation. This migration is crucial, as centrioles are responsible for organizing the microtubules that form the mitotic spindle, the structure that will eventually pull the sister chromatids apart.Rate this question:
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- 11.
What is the longest of the mitotic stages?
- A.
Telophase
- B.
Anaphase
- C.
Prometaphase
- D.
Metaphase
- E.
Prophase
Correct Answer
E. PropHaseExplanation
The correct answer is E, prophase. Prophase is the longest stage of mitosis and serves as the preparation phase where the cell makes structural changes necessary for successful chromosome division. During prophase, the chromatin—a complex of DNA and proteins—condenses into discrete, tightly packed chromosomes that become visible under a microscope. Each chromosome, by this point, has duplicated and consists of two sister chromatids joined by a centromere. Meanwhile, the nuclear envelope begins to disintegrate, signaling the end of the nucleus as a barrier to spindle fibers, and the nucleolus (the site of ribosome assembly) disappears. Centrioles in animal cells also begin to separate, moving towards opposite poles to initiate the formation of the mitotic spindle apparatus, essential for chromosomal movement and alignment.Rate this question:
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- 12.
In which phase of mitosis do centromeres uncouple, sister chromatids are separated, and the two new chromosomes move to opposite poles of the cell?
- A.
Telophase
- B.
Anaphase
- C.
Prometaphase
- D.
Metaphase
- E.
Prophase
Correct Answer
B. AnapHaseExplanation
The correct answer is B, anaphase. Anaphase is a critical phase in mitosis where the sister chromatids of each chromosome are separated, allowing the cell to distribute one copy of each chromosome to each daughter cell. This separation occurs when the centromeres that connect the sister chromatids split, enabling each chromatid to move independently. Microtubules connected to the kinetochores (protein complexes at the centromeres) shorten, pulling the chromatids—now individual chromosomes—toward opposite poles of the cell. This coordinated movement ensures that each pole receives an identical set of chromosomes. By the end of anaphase, the two sets of chromosomes are at opposite ends of the cell, preparing for the final stages of cell division.Rate this question:
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- 13.
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
Correct Answer
D. MetapHaseExplanation
When cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, mitosis will be arrested at the metaphase stage. The spindle apparatus is responsible for separating the duplicated chromosomes, and in metaphase, the chromosomes align in the middle of the cell. If the spindle apparatus is not functioning properly due to the interference of colchicine, the chromosomes will not be able to separate and the cell division process will be halted.Rate this question:
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- 14.
A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei containing how many chromosomes?
- A.
12
- B.
16
- C.
23
- D.
46
- E.
92
Correct Answer
D. 46Explanation
During metaphase of mitosis, each chromatid is still attached to its sister chromatid. Since there are 92 chromatids, this means there are 46 pairs of sister chromatids. When mitosis is completed, each pair of sister chromatids separates and moves to opposite poles of the cell. This results in the formation of two nuclei, each containing 46 chromosomes. Therefore, the correct answer is 46.Rate this question:
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- 15.
If the cell whose nuclear material is shown above continues toward completion of mitosis, which of the following events would occur next?
- A.
Cell membrane synthesis
- B.
Spindle fiber formation
- C.
Nuclear envelope breakdown
- D.
Formation of telophase nuclei
- E.
Synthesis of chromatids
Correct Answer
D. Formation of telopHase nucleiExplanation
If the cell whose nuclear material is shown above continues toward completion of mitosis, the next event that would occur is the formation of telophase nuclei. Telophase is the final stage of mitosis, where the nuclear material starts to condense and form two separate nuclei. This is followed by cytokinesis, where the cell membrane divides to form two separate daughter cells.Rate this question:
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- 16.
All of the following occur during prophase of mitosis in animal cells except
- A.
The centrioles move toward opposite poles.
- B.
The nucleolus can no longer be seen.
- C.
The nuclear envelope disappears.
- D.
Chromosomes are duplicated.
- E.
The spindle is organized.
Correct Answer
D. Chromosomes are duplicated.Explanation
During prophase of mitosis in animal cells, several events occur. The centrioles move toward opposite poles, the nucleolus can no longer be seen, the nuclear envelope disappears, and the spindle is organized. However, chromosomes are not duplicated during prophase. Chromosome duplication occurs during the S phase of interphase, which is prior to mitosis.Rate this question:
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- 17.
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
Correct Answer
A. 10Explanation
Before division, sister chromatids are attached at centromeres. After separation, each chromatid becomes a daughter chromosome. During anaphase, if 20 centromeres are observed, the dividing cell has 20 chromosomes. Each pole receives 10 chromatids, making each a chromosome in the daughter cell. Thus, after cytokinesis, each daughter cell has 10 chromosomes, each consisting of a single chromatid. Therefore, the answer is '10 chromosomes.'Rate this question:
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- 18.
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
Correct Answer
A. 10Explanation
During metaphase, the chromosomes are duplicated and consist of two sister chromatids joined together. Following cytokinesis, the cell divides into two daughter cells. Each daughter cell will receive an equal number of chromosomes as the parent cell. Since there are 20 chromatids in the parent cell, there are 10 chromosomes (20 divided by 2) in each daughter cell.Rate this question:
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- 19.
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
Correct Answer
B. CentrosomeExplanation
During mitosis in both plant and animal cells, the microtubules of the spindle originate from the centrosome. The centrosome is a structure located near the nucleus that contains a pair of centrioles. These centrioles play a crucial role in organizing the microtubules and are responsible for forming the spindle apparatus. The spindle is essential for the proper alignment and separation of chromosomes during cell division. Therefore, the centrosome is the correct answer as it is the origin of the microtubules in the spindle during mitosis.Rate this question:
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- 20.
All of the following occur during mitosis except the
- A.
Condensing of chromosomes.
- B.
Uncoupling of chromatids at the centromere.
- C.
Formation of a spindle.
- D.
Synthesis of DNA.
- E.
Disappearance of the nucleolus.
Correct Answer
D. Synthesis of DNA.Explanation
During mitosis, several events occur including condensing of chromosomes, uncoupling of chromatids at the centromere, formation of a spindle, and disappearance of the nucleolus. However, synthesis of DNA does not occur during mitosis. DNA replication takes place during the S phase of the cell cycle, which precedes mitosis. In mitosis, the duplicated chromosomes are separated and distributed to two daughter cells, but no new DNA synthesis occurs.Rate this question:
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- 21.
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
Correct Answer
E. 16Explanation
During anaphase of mitosis, the sister chromatids separate and move to opposite poles of the cell. Each chromatid is considered a chromosome. Since the cell has 8 chromosomes at metaphase, during anaphase, when the sister chromatids separate, there will be a total of 16 chromosomes in the cell.Rate this question:
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- 22.
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.
Correct Answer
D. Two nuclei.Explanation
If a cell completed mitosis but not cytokinesis, it means that the cell has undergone nuclear division but not cell division. This would result in two nuclei within a single cell. Cytokinesis is the process of dividing the cytoplasm and creating two separate cells, but if it does not occur, the cell will have multiple nuclei. Therefore, the correct answer is two nuclei.Rate this question:
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- 23.
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 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.
Correct Answer
C. A cell plate begins to form at telopHase, whereas animals a cleavage furrow is initiated at that stage.Explanation
In plants, during cytokinesis, a cell plate begins to form at telophase. This cell plate eventually develops into a new cell wall, dividing the cytoplasm into two separate daughter cells. In contrast, in animals, a cleavage furrow is initiated at telophase. The cleavage furrow is a constriction that forms around the equator of the cell and deepens until it eventually pinches the cell into two daughter cells. This difference in cytokinesis is due to the structural and functional differences between plant and animal cells.Rate this question:
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- 24.
How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 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.
Correct Answer
D. The daughter cells have the same number of chromosomes and the same amount of DNA.Explanation
During mitosis and cytokinesis, the parent cell divides into two daughter cells. At the end of this process, the daughter cells have the same number of chromosomes as the parent cell. This is because the chromosomes are duplicated during the S phase of the cell cycle, and each daughter cell receives an identical set of chromosomes. Additionally, the daughter cells have the same amount of DNA as the parent cell, as the DNA is replicated during the S phase as well. Therefore, the correct answer is that the daughter cells have the same number of chromosomes and the same amount of DNA.Rate this question:
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- 25.
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
Correct Answer
E. A plant cell undergoing cytokinesisExplanation
This cell is a plant cell undergoing cytokinesis because the cell plate is forming across the middle of the cell, which is a characteristic of cytokinesis in plant cells. Additionally, the nuclei are re-forming at opposite ends of the cell, which is another characteristic of cytokinesis. This process is different from animal cells, as they form a cleavage furrow during cytokinesis instead of a cell plate. Therefore, the correct answer is a plant cell undergoing cytokinesis.Rate this question:
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- 26.
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.
Correct Answer
A. The fibers of the mitotic spindle.Explanation
Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. The fibers of the mitotic spindle are composed of microtubules and are crucial for the proper alignment and separation of chromosomes during mitosis. Therefore, when taxol affects the fibers of the mitotic spindle, it disrupts the normal process of mitosis, leading to the inhibition of cell division.Rate this question:
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- 27.
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
Correct Answer
B. Golgi-derived vesiclesExplanation
Golgi-derived vesicles are primarily responsible for cytokinesis in plant cells. During cytokinesis, these vesicles fuse together at the equatorial plane of the cell, forming a cell plate. The cell plate then expands and fuses with the existing cell wall, dividing the cytoplasm into two daughter cells. This process is unique to plant cells and is different from animal cell cytokinesis, which involves the formation of a cleavage furrow. Kinetochores, actin and myosin, centrioles and basal bodies, and cyclin-dependent kinases are not directly involved in cytokinesis in plant cells.Rate this question:
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- 28.
Which of the following organisms does not reproduce cells by mitosis and cytokinesis?
- A.
Cow
- B.
Bacterium
- C.
Mushroom
- D.
Cockroach
- E.
Banana tree
Correct Answer
B. BacteriumExplanation
Bacteria do not reproduce cells by mitosis and cytokinesis. Instead, they reproduce through a process called binary fission, where the cell divides into two identical daughter cells. Mitosis and cytokinesis are specific to eukaryotic organisms, such as animals, plants, and fungi. Bacteria are prokaryotes and have a simpler cell structure, so they use binary fission for cell reproduction.Rate this question:
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- 29.
Chromosomes first become visible during ________ of mitosis.
- A.
Prometaphase
- B.
Telophase
- C.
Prophase
- D.
Metaphase
- E.
Anaphase
Correct Answer
C. PropHaseExplanation
During prophase of mitosis, the chromosomes condense and become visible under a microscope. This is the first stage of mitosis where the nuclear envelope starts to break down and the spindle fibers begin to form, preparing for the separation of the duplicated chromosomes. Therefore, prophase is the correct answer for when chromosomes first become visible during mitosis.Rate this question:
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- 30.
The correct sequence of steps in the M phase of the cell cycle is
- A.
Prophase, prometaphase, metaphase, anaphase, telophase.
- B.
Prophase, metaphase, prometaphase, anaphase, telophase.
- C.
Prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.
- D.
Prophase, metaphase, anaphase, telophase, cytokinesis.
- E.
Cytokinesis, telophase, prophase, prometaphase, metaphase, anaphase.
Correct Answer
C. PropHase, prometapHase, metapHase, anapHase, telopHase, cytokinesis.Explanation
The M phase of the cell cycle consists of several stages, including prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis. These stages occur in a specific order. During prophase, the chromatin condenses into chromosomes, the nuclear envelope breaks down, and the mitotic spindle begins to form. Prometaphase follows, during which the nuclear envelope completely disintegrates and the spindle fibers attach to the centromeres of the chromosomes. Metaphase is the next stage, where the chromosomes align along the equator of the cell. Anaphase then occurs, where the sister chromatids separate and move towards opposite poles of the cell. Telophase follows, during which the chromosomes reach the poles of the cell and decondense, and the nuclear envelope reforms. Finally, cytokinesis takes place, where the cytoplasm divides, resulting in the formation of two daughter cells. Therefore, the correct sequence of steps in the M phase of the cell cycle is prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis.Rate this question:
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- 31.
During which phases of mitosis are chromosomes composed of two chromatids?
- A.
From interphase through anaphase
- B.
From G1 of interphase through metaphase
- C.
From metaphase through telophase
- D.
From anaphase through telophase
- E.
From G2 of interphase through metaphase
Correct Answer
E. From G2 of interpHase through metapHaseExplanation
During the G2 phase of interphase, the cell prepares for mitosis by synthesizing proteins and duplicating its organelles. At the start of mitosis, during the prophase, the chromosomes condense and become visible under a microscope. Each chromosome consists of two identical sister chromatids, which are held together by a structure called the centromere. The chromatids remain attached until they separate during the anaphase. Therefore, from the G2 phase of interphase through metaphase, the chromosomes are composed of two chromatids.Rate this question:
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- 32.
Which of the following is false regarding the bacterial chromosome?
- A.
It consists of a single, circular DNA molecule.
- B.
DNA replication begins at the origin of replication.
- C.
Its centromeres uncouple during metaphase of mitosis.
- D.
It is highly folded within the cell.
- E.
It has genes that control binary fission.
Correct Answer
C. Its centromeres uncouple during metapHase of mitosis.Explanation
The bacterial chromosome consists of a single, circular DNA molecule. DNA replication begins at the origin of replication. It is highly folded within the cell and has genes that control binary fission. However, the statement that its centromeres uncouple during metaphase of mitosis is false. Bacteria do not have centromeres like eukaryotic cells do, and they undergo a different process called binary fission for cell division, not mitosis.Rate this question:
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- 33.
In which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis?
- A.
Seedless plants
- B.
Dinoflagellates
- C.
Diatoms
- D.
B and C only
- E.
A, B, and C
Correct Answer
D. B and C onlyExplanation
The correct answer is B and C only. Dinoflagellates and diatoms are both groups of eukaryotic organisms in which the nuclear envelope remains intact during mitosis. This means that the nucleus remains enclosed within a membrane throughout the process of cell division. Seedless plants, on the other hand, do not have an intact nuclear envelope during mitosis. Therefore, the correct answer is B and C only.Rate this question:
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- 34.
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.
Correct Answer
D. Prevents shortening of microtubules.Explanation
During anaphase, the chromosomes separate and move towards opposite poles of the cell. This movement is facilitated by the shortening of microtubules, which are responsible for pulling the chromosomes apart. If a drug prevents the shortening of microtubules, it would hinder the movement of chromosomes during anaphase, as they would not be able to separate properly. Therefore, the drug that prevents shortening of microtubules would have the greatest impact on the movement of chromosomes during anaphase.Rate this question:
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- 35.
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.
G0
- B.
G1
- C.
S
- D.
G2
- E.
M
Correct Answer
D. G2Explanation
The nucleus with 6 picograms of DNA is in the G2 stage of the cell cycle. This is because the G2 stage follows the S stage, during which DNA replication occurs. In the G2 stage, the cell prepares for cell division by synthesizing proteins and organelles necessary for cell division. Since the measured DNA levels range from 3 to 6 picograms per nucleus, the nucleus with 6 picograms of DNA is likely in the G2 stage where DNA replication has already occurred.Rate this question:
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- 36.
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 G2.
- A.
8; 8
- B.
8; 16
- C.
16; 8
- D.
16; 16
- E.
12; 16
Correct Answer
D. 16; 16Explanation
During the S phase of the cell cycle, DNA replication occurs, resulting in the duplication of the DNA content. Therefore, at the end of the S phase, each cell would have 16 picograms of DNA. In the G2 phase, the cell undergoes growth and prepares for cell division. Since no further DNA replication occurs during this phase, the amount of DNA remains the same as at the end of the S phase, which is 16 picograms.Rate this question:
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- 37.
The somatic cells derived from a single-celled zygote divide by which process?
- A.
Meiosis
- B.
Mitosis
- C.
Replication
- D.
Cytokinesis alone
- E.
Binary fission
Correct Answer
B. MitosisExplanation
The somatic cells derived from a single-celled zygote divide by the process of mitosis. Mitosis is a type of cell division where a single cell divides into two identical daughter cells, each with the same number of chromosomes as the parent cell. This process is responsible for growth, repair, and maintenance of the body's tissues and organs. Meiosis, on the other hand, is a type of cell division that occurs in the formation of gametes (sperm and eggs) and leads to genetic variation. Replication refers to the duplication of DNA, while cytokinesis alone is the division of the cytoplasm. Binary fission is a type of cell division that occurs in prokaryotes, not in eukaryotic somatic cells.Rate this question:
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- 38.
Cytoskeletal elements play important roles in cell division. The mitotic spindle apparatus is made of ________ and pulls sister chromatids apart, whereas the contractile ring is made of ________ and required for the separation of daughter cells at the end of the mitotic phase of the cell cycle.
- A.
Intermediate filaments; actin microfilaments
- B.
Microtubules; actin microfilaments
- C.
Microtubules; contractile filaments
- D.
Intermediate filaments; contractile filaments
- E.
Actin microfilaments; myosin
Correct Answer
B. Microtubules; actin microfilamentsExplanation
Cytoskeletal elements, specifically microtubules, make up the mitotic spindle apparatus, which is responsible for separating sister chromatids during cell division. On the other hand, the contractile ring, which is required for the separation of daughter cells at the end of the mitotic phase, is made of actin microfilaments.Rate this question:
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- 39.
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
Correct Answer
D. MetapHaseExplanation
In metaphase of mitosis, replicated chromosomes are aligned along the center (equator) of the cell. This is consistent with the description given in the question, where the chromosomes are visible and aligned along the center in some cells. Therefore, the correct answer is metaphase.Rate this question:
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- 40.
If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will
- A.
Move directly into telophase.
- B.
Complete the cycle and divide.
- C.
Exit the cycle and switch to a nondividing state.
- D.
Show a drop in MPF concentration.
- E.
Complete cytokinesis and form new cell walls.
Correct Answer
B. Complete the cycle and divide.Explanation
If mammalian cells receive a go-ahead signal at the G1 checkpoint, it means that all the necessary conditions for cell division have been met. Therefore, the cells will continue with the cell cycle and proceed through the remaining phases (S, G2, and M) to eventually divide into two daughter cells.Rate this question:
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- 41.
Cells that are in a nondividing state are in which phase?
- A.
G0
- B.
G2
- C.
G1
- D.
S
- E.
M
Correct Answer
A. G0Explanation
Cells that are in a nondividing state are in the G0 phase. This phase represents a resting or quiescent stage in the cell cycle where cells temporarily or permanently exit the cell cycle and stop dividing. Cells in G0 phase are not actively preparing for cell division and may remain in this phase for an extended period of time, or in some cases, indefinitely.Rate this question:
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- 42.
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 MPF complexes
- E.
The binding of PDGF to receptors on the cell surface
Correct Answer
D. Its destruction by a process initiated by the activity of MPF complexesExplanation
The decrease in the amount of cyclin at a specific point in the cell cycle is caused by its destruction by a process initiated by the activity of MPF complexes. MPF complexes, also known as M-phase promoting factor, are responsible for regulating the progression of the cell cycle. Once MPF complexes become active, they trigger the degradation of cyclin, leading to its decrease. This allows the cell cycle to proceed to the next phase.Rate this question:
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- 43.
Select the term most closely related to the following phrase: released by platelets in the vicinity of an injury.
- A.
PDGF
- B.
MPF
- C.
Protein kinase
- D.
Cyclin
- E.
Cdk
Correct Answer
A. PDGFExplanation
The correct answer is PDGF (Platelet-Derived Growth Factor). PDGF is a protein that is specifically released by platelets when there is an injury, initiating the wound-healing process. It stimulates nearby cells to divide and repair the damaged area by promoting tissue repair and new blood vessel formation, which are crucial steps in wound healing.Rate this question:
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- 44.
Select the term most closely related to the following phrase: 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
Correct Answer
C. Protein kinaseExplanation
The correct answer is protein kinase. Protein kinases are enzymes that add phosphate groups to other proteins in a process known as phosphorylation. This addition can either activate or inactivate the target protein, impacting various cellular processes. While PDGF, MPF, cyclin, and Cdk are related to cell cycle regulation, protein kinase is the broad term for enzymes that phosphorylate proteins.Rate this question:
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- 45.
Select the term most closely related to the following phrase: Fibroblasts have receptors for this substance on their plasma membranes.
- A.
PDGF
- B.
MPF
- C.
Protein kinase
- D.
Cyclin
- E.
Cdk
Correct Answer
A. PDGFExplanation
The correct answer is PDGF. Fibroblasts, which are cells involved in wound healing, have receptors on their membranes for PDGF (Platelet-Derived Growth Factor). PDGF binds to these receptors and activates a signaling pathway that promotes cell growth, division, and tissue repair, aiding in the healing process by attracting fibroblasts to the injury site.Rate this question:
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- 46.
Select the term most closely related to the following phrase: 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
Correct Answer
D. CyclinExplanation
The correct answer is cyclin. Cyclins are proteins produced at specific times in the cell cycle that bind to cyclin-dependent kinases (Cdks) to form an active complex. This cyclin-Cdk complex regulates the progression of the cell cycle by activating various target proteins involved in cell division.Rate this question:
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- 47.
Select the term most closely related to the following phrase: 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
Correct Answer
E. CdkExplanation
The correct answer is Cdk (Cyclin-dependent kinase). Cdks are enzymes that are present at constant levels throughout the cell cycle. However, they require cyclin to form an active cyclin-Cdk complex that can phosphorylate other proteins, driving the cell through the stages of the cell cycle.Rate this question:
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- 48.
Select the term most closely related to the following phrase: triggers the cell's passage past the G2 checkpoint into mitosis.
- A.
PDGF
- B.
MPF
- C.
Protein kinase
- D.
Cyclin
- E.
Cdk
Correct Answer
B. MPFExplanation
The correct answer is MPF (Maturation Promoting Factor). MPF is a protein complex that includes Cdk and cyclin, and it is responsible for pushing the cell past the G2 checkpoint into the M phase (mitosis). MPF activation initiates mitosis, allowing for cell division to proceed.Rate this question:
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- 49.
Select the term most closely related to the following phrase: The "restriction point" occurs here.
- A.
G0
- B.
G1
- C.
S
- D.
G2
- E.
M
Correct Answer
B. G1Explanation
The correct answer is G1. The "restriction point" is a checkpoint in the G1 phase of the cell cycle where the cell decides whether to continue to the S phase for DNA replication or enter the G0 phase, where it will not divide. If conditions are favorable, the cell will proceed through the cell cycle; otherwise, it may exit the cycle temporarily or permanently.Rate this question:
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- 50.
Select the term most closely related to the following phrase: Nerve and muscle cells are in this phase
- A.
G0
- B.
G1
- C.
S
- D.
G2
- E.
M
Correct Answer
A. G0Explanation
The correct answer is G0. The G0 phase is a resting state in the cell cycle where cells are not actively dividing. Nerve and muscle cells, which typically do not divide after maturity, remain in the G0 phase, where they carry out their specific functions without preparing for cell division.Rate this question:
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.webp "The lettered circle in the figure above 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 stage.
*At prometaphase of mitosis")
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Oct 30, 2024Quiz Edited by
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