Question 1

Which of the following best describes the main purpose of mitosis in multicellular organisms?

Accepted Answer

To enable growth, repair of tissues, and asexual reproduction by producing genetically identical daughter cells

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the result?

Accepted Answer

S phase; chromosomes are duplicated

Question 3

A scientist observes a cell with condensed chromosomes aligned at the center of the cell. Which stage of mitosis is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following statements about the G1 checkpoint is correct?

Accepted Answer

It checks for sufficient nutrients, growth factors, adequate cell size, and undamaged DNA before allowing the cell to proceed to S phase.

Question 5

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

Accepted Answer

They become active when bound to cyclins and phosphorylate target proteins to regulate cell cycle progression.

Question 6

A mutation in a proto-oncogene results in a protein that is always active. What is the likely consequence?

Accepted Answer

The cell may divide uncontrollably, contributing to tumor formation.

Question 7

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

Accepted Answer

Multiple mutations (hits) in cell cycle control genes accumulate over time, increasing the risk of cancer.

Question 8

Which of the following is NOT a hallmark of cancer cells?

Accepted Answer

Ability to differentiate into specialized cell types

Question 9

A cell is observed to have an abnormal number of chromosomes and an enlarged nucleus. What is the most likely explanation?

Accepted Answer

The cell is likely cancerous, as these are common abnormalities in cancer cells.

Question 10

Which checkpoint ensures that all chromosomes are properly attached to the spindle before the cell proceeds with division?

Accepted Answer

Metaphase (spindle) checkpoint

Question 11

If a cell fails to pass the G2 checkpoint due to incomplete DNA replication, what is the most likely outcome?

Accepted Answer

The cell will attempt to repair the DNA or halt the cell cycle.

Question 12

Which of the following best describes the function of tumor suppressor genes?

Accepted Answer

They encode proteins that repair DNA, promote apoptosis, or halt the cell cycle to prevent uncontrolled division.

Question 13

A patient is diagnosed with a malignant tumor. Which characteristic distinguishes this tumor from a benign tumor?

Accepted Answer

It has the ability to metastasize and spread to other parts of the body.

Question 14

Which of the following is a real-world example of a mutagen that can increase cancer risk?

Accepted Answer

Ultraviolet (UV) light

Question 15

Which equation best represents the relationship between cyclin concentration and MPF activity?

Accepted Answer

$$	ext{MPF Activity} \propto [	ext{Cyclin}]$$

Question 16

A cell exposed to a virus that inactivates the p53 protein is likely to:

Accepted Answer

Fail to repair DNA damage and continue dividing, increasing cancer risk

Question 17

Which of the following best explains why lifestyle factors such as smoking increase cancer risk?

Accepted Answer

Smoking introduces chemical mutagens that increase the likelihood of mutations in cell cycle control genes.

Question 18

Which process is responsible for the separation of sister chromatids during mitosis?

Accepted Answer

Microtubules shorten at the kinetochore, pulling chromatids apart.

Question 19

A cell is observed to be in G0 phase. Which of the following best describes its state?

Accepted Answer

It is arrested and not dividing, but still performing normal functions.

Question 20

Which of the following is a direct consequence if the metaphase (spindle) checkpoint fails?

Accepted Answer

Cells may divide with unequal distribution of chromosomes, leading to aneuploidy.

Mitosis, the Cell Cycle, and Cancer: Regulation and Consequences of Cell Division

Study Guide - Practice Questions