Question 1

Which of the following best explains why gametes contain half as many chromosomes as somatic cells?

Accepted Answer

Because gametes are produced by meiosis, which reduces the chromosome number by half to maintain species stability across generations.

Question 2

During which phase of mitosis do the cohesins holding sister chromatids together get cleaved, and what enzyme is responsible for this process?

Accepted Answer

Anaphase; separase

Question 3

A researcher observes a eukaryotic cell with chromosomes aligned at the center of the cell, spindle fibers attached to kinetochores, and centrosomes at opposite poles. Which phase is the cell most likely in?

Accepted Answer

Metaphase

Question 4

Which of the following structures is NOT part of the mitotic spindle apparatus in animal cells?

Accepted Answer

Nucleolus

Question 5

In prokaryotic binary fission, what is the correct sequence of events?

Accepted Answer

Chromosome replication begins at the origin of replication, daughter chromosomes move apart, plasma membrane pinches inward, cell divides.

Question 6

Which of the following statements about the cell cycle control system is correct?

Accepted Answer

It ensures that the cell cycle proceeds only when certain internal and external conditions are met, using checkpoints.

Question 7

A mutation prevents the formation of kinetochores in a eukaryotic cell. Which of the following would most likely occur during mitosis?

Accepted Answer

Sister chromatids would not attach to spindle microtubules, preventing proper chromosome segregation.

Question 8

Which of the following best describes the difference between chromatin and chromosomes in eukaryotic cells?

Accepted Answer

Chromatin is the uncondensed complex of DNA and protein, while chromosomes are condensed structures visible during cell division.

Question 9

If a human somatic cell contains 46 chromosomes, how many chromosomes would you expect to find in a human gamete?

Accepted Answer

$$23$$

Question 10

Which of the following events occurs during interphase of the cell cycle?

Accepted Answer

DNA is replicated in preparation for cell division.

Question 11

A scientist treats animal cells with a drug that prevents centrosome replication. What is the most likely effect on mitosis?

Accepted Answer

The mitotic spindle would not form properly, leading to errors in chromosome segregation.

Question 12

Which of the following is a key difference between mitosis and binary fission?

Accepted Answer

Mitosis involves the formation of a mitotic spindle, while binary fission does not.

Question 13

Which checkpoint in the cell cycle is most critical for preventing the division of cells with damaged DNA?

Accepted Answer

The G1 checkpoint

Question 14

If the enzyme separase is inhibited during mitosis, what is the most likely outcome?

Accepted Answer

Sister chromatids will fail to separate during anaphase.

Question 15

Which of the following best describes the role of the centromere during mitosis?

Accepted Answer

It is the region where sister chromatids are most closely attached and where kinetochores form.

Question 16

A cell is observed to have two centrosomes, each with an aster, and chromosomes beginning to condense. Which phase is this cell most likely in?

Accepted Answer

Prophase

Question 17

Which of the following is true regarding the genome of a prokaryotic cell?

Accepted Answer

It typically consists of a single DNA molecule.

Question 18

During which stage of mitosis do spindle microtubules attach to kinetochores?

Accepted Answer

Prometaphase

Question 19

Which of the following best explains why the mitotic spindle is essential for cell division in eukaryotes?

Accepted Answer

It ensures accurate segregation of duplicated chromosomes to daughter cells.

Question 20

A mutation causes the cohesins between sister chromatids to be degraded prematurely during mitosis. What is the most likely consequence?

Accepted Answer

Chromosomes may not align properly at the metaphase plate, leading to unequal chromosome segregation.

The Cell Cycle and Cell Division

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