Cell Cycle and Cell Division MCQs with Explanations
Here are some multiple-choice questions (MCQs) about the Cell Cycle and Cell Division with explanations to help you understand better:
Q1. In oocytes of some vertebrates, the arrest phase can last for months or years.
A. Diplotene
B. Zygotene
C. Pachytene
D. Diakinesis
Answer: A. Diplotene
Explanation: In some vertebrates, oocytes are arrested in the diplotene stage of prophase I of meiosis, and this arrest can last for extended periods.
Q2. A daughter cell has 23 pairs of chromosomes after cytokinesis. The number of chromatids at the preceding metaphase would be:
A. 23
B. 69
C. 46
D. 92
Answer: D. 92
Explanation: Since the chromosome number in metaphase is double that of the daughter cells, the number of chromatids would be 92.
Q3. The correct sequence of phases of the cell cycle is:
A. G1 → G2 → S → M
B. M → G1 → G2 → S
C. G1 → S → G2 → M
D. S → G1 → G2 → M
Answer: C. G1 → S → G2 → M
Explanation: The correct sequence of the cell cycle phases is G1 (growth phase 1), S (synthesis phase), G2 (growth phase 2), and M (mitosis phase).
Q4. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
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Assertion A: During the cell cycle, cells in the G0 phase no longer proliferate unless called on to do so.
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Reason R: Cells in the G0 stage of interphase remain metabolically inactive.
In the light of the above statements, choose the correct answer from the options given below:
A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true but R is NOT the correct explanation of A.
Answer: A. A is true but R is false.
Explanation: Cells in the G0 phase are in a resting state and do not actively proliferate unless signaled to do so, but they are not metabolically inactive.
Q5. Which of the following cells in an adult animal do not show cell division?
A. Heart cells
B. Upper layer of epidermis
C. Bone marrow cells
D. Cells of the lining of the gut
Answer: A. Heart cells
Explanation: Heart cells generally do not divide after the heart has developed, making them non-proliferative in adulthood.
Q6. If a parental cell is having 8 pairs of chromosomes, then the number of chromatids in anaphase I of meiosis and anaphase of mitosis respectively will be:
A. 32 and 32
B. 16 and 16
C. 16 and 32
D. 32 and 16
Answer: C. 16 and 32
Explanation: In anaphase I of meiosis, the chromatids are still held together by centromeres, so the total number of chromatids is 32. In mitosis, the chromatids are separated, so the number is 16.
Q7. If a cell is diploid (2n) having a total of 40 chromosomes, how many chromosomes will be received by daughter cells formed after meiosis I and daughter cells formed after meiosis II respectively?
A. 20 & 10
B. 20 & 20
C. 40 & 20
D. 40 & 10
Answer: A. 20 & 10
Explanation: After meiosis I, the chromosomes are halved to 20. After meiosis II, each daughter cell will get 20 chromosomes.
Q8. Which of the following is correct regarding the quiescent phase?
A. Cell will exit from S phase
B. Cell will exit from G2 phase
C. Cell will enter in M phase without replication
D. Cell will exit from G1 phase
Answer: D. Cell will exit from G1 phase
Explanation: The quiescent phase refers to the G0 phase, where cells are not actively dividing or preparing to divide, effectively exiting the cell cycle from the G1 phase.
Q9. Select the correct statements with respect to the cell cycle.
I. The interphase lasts not more than 50% of the duration of the cell cycle.
II. Plants can show mitotic divisions in both haploid and diploid cells.
III. G2 phase corresponds to the interval between mitosis and initiation of DNA replication.
IV. S or synthesis phase marks the period during which DNA synthesis or replication takes place.
Choose the most appropriate answer from the options given below:
A. I and III only
B. I and IV only
C. I and II only
D. II and IV only
Answer: D. II and IV only
Explanation: The correct answer is D. In plants, both haploid and diploid cells can undergo mitosis, and the S phase is when DNA replication occurs.
Q10. If a parent cell is having 8 pairs of chromosomes, then how many centromeres will be observed under a microscope at anaphase II of meiosis?
A. 16
B. 8
C. 32
D. 4
Answer: A. 16
Explanation: In anaphase II of meiosis, the centromeres are split, so 16 centromeres will be visible.
Q11. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
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Assertion (A): Zygotene is characterized by the formation of the synaptonemal complex.
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Reason (R): Synaptonemal complex helps in synapsis of non-homologous chromosomes.
In the light of the above statements, choose the correct answer from the options given below:
A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true but R is NOT the correct explanation of A.
Answer: A. A is true but R is false.
Explanation: The synaptonemal complex helps in the pairing of homologous chromosomes, not non-homologous chromosomes.
Q12. Four haploid cells are formed at the end of:
A. Meiosis II
B. Meiosis I
C. Mitosis
D. Telophase
Answer: A. Meiosis II
Explanation: Four haploid cells are formed at the end of meiosis II after the separation of sister chromatids.
Q13. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
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Assertion (A): Crossing over between homologous chromosomes is seen in pachytene.
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Reason (R): Meiosis ensures genetic variation in population.
In the light of the above statements, choose the correct answer from the options given below:
A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true but R is NOT the correct explanation of A.
Answer: C. Both A and R are true and R is the correct explanation of A.
Explanation: Crossing over occurs during pachytene and is a key process in generating genetic variation during meiosis.
Q14. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
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Assertion (A): Prophase-I is typically longer as compared to mitotic prophase.
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Reason (R): Prophase-I is divided into further five stages.
In the light of the above statements, choose the correct answer from the options given below:
A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true but R is NOT the correct explanation of A.
Answer: C. Both A and R are true and R is the correct explanation of A.
Explanation: Prophase-I of meiosis is longer than mitotic prophase, and it is divided into five stages: leptotene, zygotene, pachytene, diplotene, and diakinesis.
Q15. Given below are two statements:
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Statement I: Variations are very important for the process of evolution.
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Statement II: Mitosis is also known as equational division.
In the light of the above statements, choose the most appropriate answer from the options given below:
A. Statement I is correct but Statement II is incorrect.
B. Statement I is incorrect but Statement II is correct.
C. Both Statement I and Statement II are correct.
D. Both Statement I and Statement II are incorrect.
Answer: C. Both Statement I and Statement II are correct.
Explanation: The correct answer is C. Variations are essential for evolution, and mitosis is called equational division because it maintains the same chromosome number in daughter cells.
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