Question 1

Which of the following best describes the main difference between cell division in prokaryotes and eukaryotes?

Accepted Answer

Prokaryotic cell division is generally a response to environmental conditions, while eukaryotic cell division is regulated according to the needs of the entire organism.

Question 2

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

Accepted Answer

S phase

Question 3

A scientist observes a cell with chromosomes aligned at the metaphase plate and spindle fibers attached to kinetochores. Which phase is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following is a direct result of the activation of the anaphase-promoting complex (APC) during mitosis?

Accepted Answer

Hydrolysis of cohesin proteins, allowing sister chromatids to separate

Question 5

If a cell in G2 phase contains 2.0 pg of DNA, how much DNA did it contain in G1 phase?

Accepted Answer

$$1.0\ \mathrm{pg}$$

Question 6

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

Accepted Answer

They have mutations that inactivate tumor suppressor proteins and/or activate oncogenes.

Question 7

Which protein acts as a negative regulator of the cell cycle and is inactivated by phosphorylation at the restriction point?

Accepted Answer

Retinoblastoma protein (RB)

Question 8

A drug that inhibits the formation of microtubules would most directly interfere with which process?

Accepted Answer

Chromosome segregation during mitosis

Question 9

Which of the following events occurs during apoptosis but NOT necrosis?

Accepted Answer

Formation of membrane blebs and fragmentation into vesicles

Question 10

Which of the following best describes the role of cyclin-dependent kinases (CDKs) in the cell cycle?

Accepted Answer

They phosphorylate target proteins only when bound to cyclins, regulating cell cycle transitions.

Question 11

A mutation causes a cell to produce less cyclin during G1. What is the most likely consequence?

Accepted Answer

Decreased CDK activity and more cells arrested at the restriction point

Question 12

Which of the following is a real-world example of cell division contributing to regeneration?

Accepted Answer

Regrowth of a lizard's tail after injury

Question 13

Which of the following statements about cytokinesis is correct?

Accepted Answer

In animal cells, a contractile ring of actin and myosin pinches the cell in two.

Question 14

Which of the following best explains why combination drug therapy is often used to treat cancer?

Accepted Answer

It targets multiple mutations and stages of the cell cycle present in different cancer cells.

Question 15

Which of the following is a function of the p53 protein in the cell cycle?

Accepted Answer

It is a transcription factor that helps pause the cell cycle for DNA repair.

Question 16

Which of the following is a likely outcome if a cell's RB protein is inactivated by a viral protein?

Accepted Answer

The cell will proceed through the restriction point even if conditions are not appropriate.

Question 17

Which of the following best describes the role of caspases in apoptosis?

Accepted Answer

They hydrolyze nuclear and cytoskeletal proteins, leading to cell fragmentation.

Question 18

Which of the following is a characteristic of malignant tumors but NOT benign tumors?

Accepted Answer

They can metastasize and invade distant tissues.

Question 19

Which of the following drugs would most directly block DNA synthesis in cancer cells?

Accepted Answer

5-fluorouracil

Question 20

Which of the following is a direct effect of growth factors such as platelet-derived growth factor (PDGF) on target cells?

Accepted Answer

They activate signal transduction pathways that lead to cyclin synthesis and cell division.

The Cell Cycle and Cell Division: Regulation, Mechanisms, and Implications

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