Question 1

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

Accepted Answer

DNA replication occurs during the S phase, and its primary purpose is to ensure each daughter cell receives a complete set of chromosomes.

Question 2

Which checkpoint ensures that the cell is ready to enter mitosis, and what is checked at this point?

Accepted Answer

The G2/M checkpoint checks for DNA replication completion and DNA damage.

Question 3

What is the main event that distinguishes metaphase from anaphase during mitosis?

Accepted Answer

Chromosomes align at the cell's equator during metaphase, while sister chromatids separate and move to opposite poles during anaphase.

Question 4

If a cell fails to pass the G1 checkpoint, what is the most likely outcome?

Accepted Answer

The cell will enter a resting state called G0.

Question 5

Which structure is responsible for organizing the mitotic spindle during prophase?

Accepted Answer

Centrosome

Question 6

During telophase, which of the following events occurs?

Accepted Answer

Nuclear envelopes reform around the separated chromosomes.

Question 7

A mutation prevents the formation of the contractile ring during cytokinesis. What is the most likely result?

Accepted Answer

The cell will fail to separate its cytoplasm, resulting in a multinucleated cell.

Question 8

Which phase of mitosis is characterized by the fragmentation of the nuclear envelope and the formation of spindle fibers?

Accepted Answer

Prophase

Question 9

If a cell has 8 chromosomes at the start of mitosis, how many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

Each daughter cell will have 8 chromosomes.

Question 10

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

Accepted Answer

Kinetochores attach chromosomes to spindle fibers, facilitating their movement during mitosis.

Question 11

A cell is observed with chromosomes aligned at the center of the cell, spindle fibers attached, and no nuclear envelope. Which phase is this cell in?

Accepted Answer

Metaphase

Question 12

Which equation best represents the relationship between the number of chromosomes before and after mitosis?

Accepted Answer

If $$n is $$the number of chromosomes before mitosis, then after mitosis, each daughter cell has $$n$$ chromosomes: $$n \rightarrow n$$

Question 13

Which phase of the cell cycle is most likely to be affected by a drug that inhibits DNA polymerase?

Accepted Answer

S phase

Question 14

During which phase of mitosis do sister chromatids separate and move toward opposite poles?

Accepted Answer

Anaphase

Question 15

Which of the following events occurs during early prophase?

Accepted Answer

Chromatin condenses into visible chromosomes.

Question 16

A cell is exposed to a toxin that prevents spindle fiber formation. What is the most likely consequence during mitosis?

Accepted Answer

Chromosomes will fail to align and separate properly, leading to abnormal chromosome distribution.

Question 17

Which of the following best describes cytokinesis?

Accepted Answer

Cytokinesis is the division of the cytoplasm, resulting in two separate daughter cells.

Question 18

If a cell spends 90% of its time in interphase, what fraction of its life cycle is spent in mitosis?

Accepted Answer

The cell spends $$\frac{1}{10} of $$its life cycle in mitosis.

Question 19

Which of the following is NOT a function of the G2 phase?

Accepted Answer

DNA replication.

Cell Cycle and Mitosis: Structure and Phases

Study Guide - Practice Questions