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.

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 center of the cell, 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 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 best explains why cancer cells can divide uncontrollably?

Accepted Answer

They have mutations that disrupt normal cell cycle control mechanisms.

Question 9

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

Accepted Answer

They regulate the timing of the cell cycle in conjunction with cyclins.

Question 10

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

Accepted Answer

$$2n \rightarrow 2n$$

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 is a function of tumor-suppressor genes?

Accepted Answer

They inhibit cell division and repair damaged DNA.

Question 13

Which of the following best describes binary fission in bacteria?

Accepted Answer

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

Question 14

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

Accepted Answer

Gene amplification, point mutation, or translocation

Question 15

A cell is unable to pass the M checkpoint. What is the most likely reason?

Accepted Answer

Not all chromosomes are properly attached to the spindle microtubules.

Question 16

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 cancer.

Question 17

Which of the following is a real-world example of the importance of cell division in multicellular organisms?

Accepted Answer

Healing a cut on the skin through tissue renewal.

Question 18

If a cell has 8 chromosomes at the start of G1, how many chromatids will it have at the end of S phase?

Accepted Answer

$$16$$

Question 19

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

Accepted Answer

It separates sister chromatids and moves them to opposite poles of the cell.

Question 20

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

Accepted Answer

Increased predisposition to certain cancers due to impaired DNA repair.

The Cell Cycle and Molecular Biology of Cancer: Study Notes

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