Question 1

Which phase of the cell cycle is primarily responsible for the replication of DNA, and what is the significance of this process for mitosis?

Accepted Answer

S phase; it creates identical copies of the genome for daughter cells.

Question 2

During mitosis, what event marks the transition from metaphase to anaphase?

Accepted Answer

Splitting of the centromere and separation of sister chromatids.

Question 3

A cell with 2n=4 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

$$4$$

Question 4

Which checkpoint ensures that DNA is not damaged before the cell commits to division, and what happens if damage is detected?

Accepted Answer

G2 checkpoint; cell repairs DNA or undergoes apoptosis.

Question 5

What is the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are genetically unique chromosomes from each parent; sister chromatids are identical copies formed during DNA replication.

Question 6

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental strand and one new strand.

Question 7

If a mutation occurs during the S phase and is not repaired, what is the most likely outcome for the daughter cells after mitosis?

Accepted Answer

Both daughter cells will inherit the mutation.

Question 8

Which process is responsible for the separation of sister chromatids during mitosis, and what cellular structure facilitates this movement?

Accepted Answer

Anaphase; spindle fibers attached to kinetochores.

Question 9

A skin injury triggers cell division for healing. Which type of cell division is involved, and what is the genetic relationship between the new cells and the original cells?

Accepted Answer

Mitosis; new cells are genetically identical to the original cells.

Question 10

Which phase of mitosis is characterized by the reformation of the nuclear envelope and decondensation of chromosomes?

Accepted Answer

Telophase

Question 11

What is the function of the M checkpoint in the cell cycle?

Accepted Answer

Ensures chromosomes are properly aligned before separation.

Question 12

In a human cell, how many pairs of homologous chromosomes are present, and what is the total chromosome number?

Accepted Answer

$$23$$ pairs; $$46$$ total chromosomes.

Question 13

Which event occurs during prometaphase of mitosis?

Accepted Answer

Nuclear envelope breaks down and spindle fibers attach to chromosomes.

Question 14

What is the role of transcription factors in cell differentiation during development?

Accepted Answer

They regulate which genes are expressed, leading to specialized cell functions.

Question 15

Which of the following statements about the ploidy of somatic cells is correct?

Accepted Answer

Somatic cells are diploid ($$2n$$), containing one set of chromosomes from each parent.

Question 16

During DNA replication, what is the function of the replication fork?

Accepted Answer

It is the site where the parental DNA strands are separated and new strands are synthesized.

Question 17

A cell fails the G1 checkpoint due to DNA damage. What are the possible outcomes for this cell?

Accepted Answer

The cell will attempt to repair the DNA or undergo apoptosis.

Question 18

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

Accepted Answer

They bypass cell cycle checkpoints, allowing division even when errors are present.

Question 19

If a cell has completed DNA replication but chromosomes are not properly aligned, which checkpoint will prevent the cell from proceeding to division?

Accepted Answer

M checkpoint

Cell Cycle, DNA Replication, and Mitosis: Study Guide for General Biology

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