Question 1

Which of the following best describes the role of the mitotic spindle during mitosis?

Accepted Answer

It organizes and separates chromosomes by attaching to kinetochores and pulling sister chromatids apart.

Question 2

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 3

A cell is observed with condensed chromosomes aligned at the center of the cell, each attached to spindle fibers from opposite poles. Which phase is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following statements about sister chromatids is correct?

Accepted Answer

They are identical copies of a chromosome joined at the centromere.

Question 5

What is the primary difference between cytokinesis in plant and animal cells?

Accepted Answer

Animal cells form a cleavage furrow, while plant cells form a cell plate.

Question 6

Which checkpoint in the cell cycle is most critical for determining whether a cell will proceed to divide?

Accepted Answer

G1 checkpoint

Question 7

A mutation in the p53 gene can lead to cancer because:

Accepted Answer

p53 normally suppresses the cell cycle and initiates DNA repair or apoptosis if damage is detected.

Question 8

Which of the following best explains why cancer cells can divide uncontrollably?

Accepted Answer

They ignore cell cycle checkpoints due to mutations in genes like proto-oncogenes and tumor suppressors.

Question 9

What is the function of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

They phosphorylate target proteins to regulate progression through the cell cycle.

Question 10

Which of the following equations correctly represents the change in chromosome number during mitosis in a human somatic cell?

Accepted Answer

$$2n \rightarrow 4n \rightarrow 2n$$

Question 11

A researcher observes a cell with two nuclei forming and chromosomes beginning to uncoil. Which phase is this?

Accepted Answer

Telophase

Question 12

Which of the following is a key event that distinguishes anaphase from other mitotic phases?

Accepted Answer

Sister chromatids are separated and pulled to opposite poles.

Question 13

Which of the following is NOT a function of tumor-suppressor proteins?

Accepted Answer

Stimulating cell division

Question 14

Which process is most similar to eukaryotic mitosis in terms of genetic outcome, but occurs in prokaryotes?

Accepted Answer

Binary fission

Question 15

A cell is exposed to a chemical that prevents the breakdown of cohesin proteins. What is the most likely result during mitosis?

Accepted Answer

Sister chromatids will not separate during anaphase.

Question 16

Which of the following genetic changes can convert a proto-oncogene into an oncogene?

Accepted Answer

A gene duplication that increases the protein's production

Question 17

Which of the following best describes the role of the G2 checkpoint in the cell cycle?

Accepted Answer

It checks that DNA has been completely replicated and is undamaged before mitosis.

Question 18

A patient inherits a mutant allele of the BRCA1 gene. What is the most likely consequence?

Accepted Answer

Increased risk of developing certain cancers due to impaired DNA repair.

Question 19

Which of the following best explains why the incidence of cancer increases with age?

Accepted Answer

Multiple mutations accumulate over time, increasing the likelihood of cancerous transformation.

Question 20

Which of the following is a real-world example of a growth factor influencing the cell cycle?

Accepted Answer

Platelet-derived growth factor (PDGF) stimulating fibroblast division during wound healing.

The Cell Cycle and Molecular Biology of Cancer: Study Notes for General Biology

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