Question 1

Which of the following best describes the difference between chromosomes, chromatin, and chromatids?

Accepted Answer

Chromosomes are the entire DNA molecule plus associated proteins, chromatin is the actively expressed part of the chromosome, and chromatids are the duplicated copies attached at the centromere.

Question 2

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

Accepted Answer

S phase

Question 3

What would be the consequence if cytokinesis did not occur after mitosis in an animal cell?

Accepted Answer

The cell would become multinucleated, containing multiple nuclei within a single cytoplasm.

Question 4

Which checkpoint in the cell cycle ensures that all chromosomes are properly attached to the spindle before proceeding to anaphase?

Accepted Answer

M checkpoint (spindle checkpoint)

Question 5

Bacteria divide by binary fission. Which of the following is TRUE about binary fission?

Accepted Answer

It results in two genetically identical daughter cells from a single circular chromosome.

Question 6

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 7

The semiconservative model of DNA replication states that:

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 8

In eukaryotic cells, what is the function of telomeres?

Accepted Answer

They protect chromosome ends from degradation and prevent fusion with other chromosomes.

Question 9

Which of the following best describes the synthesis of the lagging strand during DNA replication?

Accepted Answer

It is synthesized discontinuously as Okazaki fragments in the 5' to 3' direction.

Question 10

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

Accepted Answer

Anaphase

Question 11

A cell in G$$_0$$ phase is best described as:

Accepted Answer

Resting and not actively preparing to divide.

Question 12

Which protein is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

Ligase

Question 13

In plant cells, cytokinesis is accomplished by:

Accepted Answer

Assembly of a cell plate from vesicles that fuse at the center of the cell.

Question 14

Which of the following statements about the cell cycle is correct?

Accepted Answer

Some cells, such as neurons and muscle cells, enter G$$_0$$ and do not divide again.

Question 15

If a mutation prevents the cleavage of cohesion proteins during mitosis, what is the most likely outcome?

Accepted Answer

Sister chromatids will fail to separate during anaphase.

Question 16

Which of the following is a correct sequence of events during mitosis?

Accepted Answer

Prophase → Metaphase → Anaphase → Telophase

Question 17

Which of the following best explains why stem cells are important for tissue repair?

Accepted Answer

They can divide and differentiate into specialized cell types needed for tissue regeneration.

Question 18

Which of the following equations correctly represents the number of chromosomes in a human somatic cell after S phase but before mitosis?

Accepted Answer

There are 46 chromosomes, each consisting of two sister chromatids (total DNA content is doubled, but chromosome number remains $$2n = 46).$$

Question 19

Which enzyme synthesizes the RNA primer required for DNA polymerase to begin DNA synthesis?

Accepted Answer

Primase

Question 20

A scientist observes a large cell with many nuclei but no evidence of cytokinesis. Which process most likely produced this cell?

Accepted Answer

Repeated mitosis without cytokinesis

Cell Division and DNA Replication: Structure, Function, and Mechanisms

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