$$\text{MPF activity} \propto \text{Cyclin concentration}$$

Question 1

Which of the following best describes the role of the mitotic spindle during mitosis?

Accepted Answer

It controls chromosome movement by attaching to kinetochores and separating sister chromatids.

Question 2

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

Accepted Answer

S phase

Question 3

A cell is observed to have chromosomes aligned at the metaphase plate. Which stage of mitosis is this cell in?

Accepted Answer

Metaphase

Question 4

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

Accepted Answer

Mitosis produces genetically identical daughter cells, while meiosis produces genetically diverse cells with half the chromosome number.

Question 5

Which equation correctly represents the relationship between the number of chromosomes in somatic cells ($$2n) $$and gametes ($$n$$)?

Accepted Answer

$$2n = 2 	imes n$$

Question 6

A scientist observes a cell with a cleavage furrow forming. What process is occurring?

Accepted Answer

Cytokinesis in an animal cell

Question 7

Which checkpoint in the cell cycle is most critical for determining whether a cell will proceed to divide?

Accepted Answer

G1 checkpoint

Question 8

Cancer cells often lose the ability to respond to which two types of external regulation?

Accepted Answer

Density-dependent inhibition and anchorage dependence

Question 9

Which of the following best explains why chemotherapy often causes side effects such as hair loss and gastrointestinal distress?

Accepted Answer

Chemotherapy drugs target the cell cycle, affecting all rapidly dividing cells, including normal ones.

Question 10

In binary fission, which step ensures that each daughter cell receives a complete copy of the bacterial chromosome?

Accepted Answer

The origin of replication moves to opposite ends of the cell before division.

Question 11

Which protein complex is responsible for triggering a cell’s passage past the G2 checkpoint into the M phase?

Accepted Answer

MPF (maturation-promoting factor)

Question 12

A cell is exposed to platelet-derived growth factor (PDGF). What is the most likely outcome?

Accepted Answer

The cell will be stimulated to divide.

Question 13

Which of the following statements about chromatin is correct?

Accepted Answer

Chromatin is a complex of DNA and protein that condenses during cell division.

Question 14

During anaphase, what enzyme cleaves the cohesins holding sister chromatids together?

Accepted Answer

Separase

Question 15

If a cell does not receive a go-ahead signal at the G1 checkpoint, what is the most likely fate of the cell?

Accepted Answer

It will exit the cell cycle and enter the G0 phase.

Question 16

Which of the following equations represents the relationship between cyclin concentration and MPF activity?

Accepted Answer

$$	ext{MPF activity} \propto 	ext{Cyclin concentration}$$

Question 17

Which of the following is a real-world consequence of loss of cell cycle control in cancer cells?

Accepted Answer

Cells may divide indefinitely and form tumors that invade surrounding tissues.

Question 18

A plant cell is observed forming a cell plate during cytokinesis. What is the function of the cell plate?

Accepted Answer

It forms the new cell wall between daughter cells.

Question 19

Which of the following best describes the relationship between cyclin-dependent kinases (Cdks) and cyclins?

Accepted Answer

Cdks are active only when attached to cyclins, and their activity fluctuates with cyclin concentration.

Question 20

Which of the following is a plausible explanation for why a benign tumor may not cause serious problems?

Accepted Answer

Benign tumors do not invade surrounding tissues or metastasize.

The Cell Cycle: Mechanisms and Regulation

Study Guide - Practice Questions