Question 1

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

Accepted Answer

It is the region where sister chromatids are most closely attached.

Question 2

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

Accepted Answer

S phase

Question 3

A scientist observes a cell with condensed chromosomes aligned at the metaphase plate. Which phase is the cell in?

Accepted Answer

Metaphase

Question 4

Which of the following statements about binary fission in bacteria is correct?

Accepted Answer

The single chromosome replicates, and each copy moves to opposite ends as the cell elongates.

Question 5

What is the primary difference between mitosis and meiosis in terms of genetic outcome?

Accepted Answer

Meiosis produces nonidentical daughter cells with half the chromosome number of the parent cell.

Question 6

A cell receives a stop signal at the M checkpoint. What is most likely occurring in this cell?

Accepted Answer

Some kinetochores remain unattached to spindle microtubules.

Question 7

Which of the following is a real-world example of density-dependent inhibition?

Accepted Answer

Normal skin cells stop dividing when they form a complete layer.

Question 8

If a cell is exposed to platelet-derived growth factor (PDGF), what is the expected cellular response?

Accepted Answer

The cell will be stimulated to divide.

Question 9

Which equation correctly represents the chromosome number in human somatic cells and gametes?

Accepted Answer

Somatic cells: $$2n = 46$$, Gametes: $$n = 23$$

Question 10

A researcher fuses a cell in S phase with a cell in G$$_1$$ phase. What is the most likely outcome?

Accepted Answer

The G$$_1$$ nucleus begins DNA synthesis.

Question 11

Which of the following best explains why chemotherapy often causes hair loss and digestive issues?

Accepted Answer

Chemotherapy drugs interfere with cell division in all rapidly dividing cells, including normal ones.

Question 12

During anaphase, what mechanism is responsible for the movement of chromosomes toward the spindle poles?

Accepted Answer

Depolymerization of microtubules at the kinetochore ends and action of motor proteins.

Question 13

Which of the following is true about the cell cycle control system?

Accepted Answer

It is regulated by both internal and external signals and includes checkpoints.

Question 14

A cell in culture divides indefinitely and does not respond to normal cell cycle controls. What process has this cell most likely undergone?

Accepted Answer

Transformation

Question 15

Which of the following events marks the beginning of cytokinesis in animal cells?

Accepted Answer

Appearance of the cleavage furrow

Question 16

What is the function of separase during the cell cycle?

Accepted Answer

It cleaves proteins holding sister chromatids together, triggering anaphase.

Question 17

Which of the following best describes the difference between benign and malignant tumors?

Accepted Answer

Benign tumors remain at the original site, while malignant tumors invade surrounding tissues and can metastasize.

Question 18

Which checkpoint is most important for determining whether a mammalian cell will divide?

Accepted Answer

G$$_1$$ checkpoint

Question 19

A mutation causes a cell to ignore anchorage dependence. What is a likely consequence?

Accepted Answer

The cell may divide uncontrollably, contributing to cancer.

The Cell Cycle: Mechanisms and Regulation

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