Question 1

Which of the following best describes the main purpose of the G1 phase in the eukaryotic cell cycle?

Accepted Answer

Recovery from previous division, growth in size, and accumulation of materials for DNA synthesis

Question 2

A scientist observes a cell with condensed chromosomes aligned at the center of the cell, spindle fibers attached to kinetochores, and no visible nuclear envelope. Which stage of mitosis is this cell most likely in?

Accepted Answer

Metaphase

Question 3

During which checkpoint does the cell verify that all chromosomes are properly aligned and attached to spindle fibers before proceeding with division?

Accepted Answer

M checkpoint

Question 4

Which of the following statements about apoptosis is TRUE?

Accepted Answer

It is a normal, programmed process that prevents the propagation of damaged cells.

Question 5

A mutation causes a cell to skip the S phase of interphase. What is the most likely consequence for the daughter cells after division?

Accepted Answer

They will have insufficient DNA, leading to nonviable or malfunctioning cells.

Question 6

Which of the following best explains why nerve and muscle cells typically remain in the G0 phase?

Accepted Answer

They are terminally differentiated and do not actively divide after development.

Question 7

In humans, the diploid number of chromosomes is $$2n = 46. $$What is the haploid number, and in which cells is it found?

Accepted Answer

$$n = 23$$; found only in gametes (sperm and egg cells)

Question 8

Which of the following events occurs during prophase of mitosis?

Accepted Answer

Nuclear envelope fragments and spindle fibers begin to assemble

Question 9

A researcher is studying a rapidly dividing bacterial culture. Which process is responsible for the asexual reproduction observed in these prokaryotic cells?

Accepted Answer

Binary fission

Question 10

Which of the following best describes the role of cyclins in the eukaryotic cell cycle?

Accepted Answer

They are internal regulatory proteins whose concentration fluctuates to control progression through cell cycle checkpoints.

Question 11

A cell is observed to have two nuclei, each with a full set of chromosomes, but the cytoplasm has not yet divided. Which stage has just been completed?

Accepted Answer

Telophase

Question 12

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

Accepted Answer

Mitosis involves the division of a membrane-bound nucleus, while binary fission does not.

Question 13

If a human somatic cell fails to properly align its chromosomes during metaphase, what is the most likely cellular response?

Accepted Answer

The cell will halt at the M checkpoint and may undergo apoptosis if the error cannot be corrected.

Question 14

Which of the following best explains why mitosis is essential for multicellular organisms?

Accepted Answer

It enables growth, tissue repair, and replacement of cells.

Question 15

During which stage of mitosis do the centromeres dissolve and sister chromatids become daughter chromosomes that are pulled to opposite poles?

Accepted Answer

Anaphase

Question 16

A plant cell is observed under a microscope. The chromosomes are decondensing, the spindle apparatus is disappearing, and a new nuclear envelope is forming around each set of chromosomes. What stage is this cell in?

Accepted Answer

Telophase

Question 17

Which of the following is TRUE regarding the chromosome number in different species?

Accepted Answer

Each species has a characteristic chromosome number, which does not necessarily correlate with organism size or complexity.

Question 18

Which structure is responsible for organizing the microtubules that separate chromosomes during mitosis in animal cells?

Accepted Answer

Centrosome (forming asters)

Question 19

A cell is exposed to a chemical that inhibits the formation of microtubules. Which stage of the cell cycle would be most directly affected?

Accepted Answer

Mitosis, particularly metaphase and anaphase

Question 20

Which of the following best describes the structure of a nucleosome?

Accepted Answer

A segment of DNA wound around a core of eight histone proteins

The Cell Cycle and Cellular Division: Mitosis and Binary Fission

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