Question 1

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

Accepted Answer

It is the site where spindle fibers attach to pull sister chromatids apart during anaphase.

Question 2

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

Accepted Answer

S phase

Question 3

A cell is observed with chromosomes aligned at the metaphase plate. Which structure is responsible for moving the chromosomes to this position?

Accepted Answer

Mitotic spindle microtubules

Question 4

Which of the following statements about sister chromatids is correct?

Accepted Answer

They are identical copies of a chromosome joined together by cohesin proteins.

Question 5

What is the main 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 divide?

Accepted Answer

G1 checkpoint

Question 7

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

Accepted Answer

Cells with damaged DNA are allowed to continue dividing.

Question 8

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

Accepted Answer

$$2n \rightarrow 2n$$

Question 9

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

Accepted Answer

They have mutations that disrupt normal cell cycle checkpoints.

Question 10

Which of the following is a function of tumor-suppressor genes?

Accepted Answer

They inhibit cell division and repair damaged DNA.

Question 11

A researcher observes a cell with a visible nucleolus, uncondensed chromatin, and two centrosomes. Which phase is this cell most likely in?

Accepted Answer

Interphase

Question 12

Which of the following best describes the process of binary fission in bacteria?

Accepted Answer

The chromosome replicates and the cell divides into two genetically identical cells.

Question 13

Which of the following is true regarding the role of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

Cdks must bind to cyclins to become active and regulate cell cycle transitions.

Question 14

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 fail to separate during anaphase.

Question 15

Which of the following best describes the function of the mitotic spindle?

Accepted Answer

It organizes and separates chromosomes during mitosis.

Question 16

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

Accepted Answer

Gene amplification, point mutation, or translocation

Question 17

Which of the following is a direct result of the activity of maturation-promoting factor (MPF) at the G2 checkpoint?

Accepted Answer

The cell enters the M phase and begins mitosis.

Question 18

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

Accepted Answer

Increased predisposition to certain cancers due to reduced inhibition of cell division.

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 key difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are inherited from different parents, while sister chromatids are identical copies formed during DNA replication.

The Cell Cycle and Molecular Biology of Cancer: Study Notes

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