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 a clearly visible nuclear envelope, nucleolus, and uncondensed chromatin. Which stage of the cell cycle is this cell most likely in?

Accepted Answer

Interphase

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

If a human somatic cell (body cell) is about to enter mitosis, how many chromatids will be present after the S phase is complete?

Accepted Answer

$$92$$

Question 5

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

Accepted Answer

Mitosis involves the condensation of chromatin into visible chromosomes, while binary fission does not.

Question 6

A mutation causes a cell to lose the ability to undergo apoptosis. What is a likely consequence of this mutation during the cell cycle?

Accepted Answer

The cell may continue to divide despite having DNA damage, increasing the risk of cancer.

Question 7

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

Accepted Answer

They do not actively divide after development and instead grow by increasing cell size.

Question 8

What is the role of cyclins in the regulation of the eukaryotic cell cycle?

Accepted Answer

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

Question 9

A cell is observed with chromosomes lined up along the metaphase plate, spindle fibers attached to kinetochores, and no nuclear envelope. Which stage is this cell in?

Accepted Answer

Metaphase

Question 10

Which of the following statements about chromosome number is correct?

Accepted Answer

The diploid number ($$2n) is $$always twice the haploid number ($$n).$$

Question 11

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 12

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

Accepted Answer

A core of eight histone proteins with DNA wound around it

Question 13

A researcher is studying a plant cell undergoing cytokinesis. Which of the following would she most likely observe?

Accepted Answer

Formation of a cell plate between the two daughter nuclei

Question 14

Which of the following is NOT a function of mitosis in multicellular organisms?

Accepted Answer

Production of genetically diverse gametes

Question 15

If a cell fails the G2 checkpoint due to unrepairable DNA damage, what is the most likely outcome?

Accepted Answer

The cell will undergo apoptosis to prevent propagation of the error.

Question 16

Which of the following best explains why the number of chromosomes is restored to the diploid number after fertilization in humans?

Accepted Answer

Each gamete contributes $$n$$ chromosomes, so $$n + n = 2n in $$the zygote.

Question 17

Which of the following events occurs during prophase of mitosis?

Accepted Answer

Nuclear envelope fragments and spindle fibers begin to assemble

Question 18

A cell is observed to have two nuclei, each with a full set of chromosomes, but the cytoplasm has not yet divided. Which stage is this cell most likely in?

Accepted Answer

Telophase

Question 19

Which of the following statements about binary fission in prokaryotes is correct?

Accepted Answer

It results in two genetically identical daughter cells.

Question 20

A cell biologist treats dividing animal cells with a drug that prevents the formation of microtubules. Which stage of the cell cycle will be directly affected, and what is the likely result?

Accepted Answer

M phase; chromosomes will not be separated during mitosis

The Cell Cycle and Cellular Division: Mitosis and Binary Fission

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