Question 1

During which phase of the cell cycle does DNA replication occur, and what is the significance of this process for mitosis?

Accepted Answer

DNA replication occurs during the S phase, allowing each daughter cell to receive a complete set of genetic instructions.

Question 2

Which checkpoint in the cell cycle ensures that all chromosomes are properly aligned before the cell proceeds with division, and what happens if this checkpoint fails?

Accepted Answer

The M checkpoint; if it fails, chromosomes may not be distributed equally, leading to aneuploidy.

Question 3

A scientist observes a cell with chromosomes lined up along the metaphase plate. Which phase of mitosis is this cell in, and what is the next major event?

Accepted Answer

Metaphase; the sister chromatids will next be separated during anaphase.

Question 4

Which of the following best describes the relationship between sister chromatids and homologous chromosomes?

Accepted Answer

Sister chromatids are genetically identical copies of a chromosome, while homologous chromosomes are similar but may have different alleles.

Question 5

If a human somatic cell (2n = 46) completes mitosis, how many chromosomes will each daughter cell have?

Accepted Answer

$$46$$

Question 6

What is the primary function of the G1 checkpoint in the cell cycle?

Accepted Answer

To check for DNA damage after mitosis and determine if the cell should proceed with division.

Question 7

Which of the following statements about DNA replication is correct?

Accepted Answer

DNA replication is semiconservative, with each new DNA molecule containing one old and one new strand.

Question 8

A mutation disables the G2 checkpoint in a cell. What is a likely consequence?

Accepted Answer

The cell may enter mitosis with damaged or unreplicated DNA, increasing the risk of cancer.

Question 9

During which stage of mitosis do the centromeres split and sister chromatids are pulled to opposite poles?

Accepted Answer

Anaphase

Question 10

Why is mitosis important for multicellular organisms?

Accepted Answer

It enables growth, tissue repair, and asexual reproduction by producing genetically identical cells.

Question 11

A cell is observed to have condensed chromosomes, a broken-down nuclear envelope, and spindle fibers attaching to kinetochores. Which phase is this?

Accepted Answer

Prometaphase

Question 12

What would happen if cytokinesis did not occur after mitosis?

Accepted Answer

The cell would have two nuclei and double the normal amount of DNA.

Question 13

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

Accepted Answer

They bypass cell cycle checkpoints that normally prevent damaged cells from dividing.

Question 14

In a plant cell, what structure forms during cytokinesis to separate the two daughter cells?

Accepted Answer

Cell plate

Question 15

Which of the following is true about the ploidy of a cell throughout mitosis?

Accepted Answer

A diploid cell remains diploid throughout mitosis and cytokinesis.

Question 16

A researcher finds a cell with twice the normal amount of DNA but only one nucleus. Which phase of the cell cycle is this cell most likely in?

Accepted Answer

S phase or G2 phase

Question 17

Which of the following events does NOT occur during mitosis?

Accepted Answer

Synthesis of DNA

Question 18

If a mutation occurs in a gene that encodes a spindle fiber protein, what is the most likely result during cell division?

Accepted Answer

Chromosomes may not align or separate properly, leading to daughter cells with abnormal chromosome numbers.

Question 19

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 20

A skin injury triggers rapid cell division in the epidermis. Which process is responsible for producing new, genetically identical skin cells?

Accepted Answer

Mitosis

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

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