what happens during the s phase of the cell cycle

HESI A2

HESI A2 Practice Test Biology

1. What happens during the S phase of the cell cycle?

A. Chromosomes are duplicated.
B. Cell growth occurs.
C. DNA is synthesized.
D. DNA is destroyed.

Correct answer: A

Rationale: During the S phase of the cell cycle, chromosomes are duplicated. This is a critical step in cell division as each chromosome is replicated to ensure that the resulting daughter cells receive an identical set of genetic information. Choices B, C, and D are incorrect because cell growth primarily occurs in the G1 phase, DNA synthesis happens during the S phase, and DNA destruction does not occur during any phase of the cell cycle.

2. What is the term for the breakdown of glycogen into glucose subunits?

A. Hydrolysis
B. Reduction
C. Metabolism
D. Transpiration

Correct answer: A

Rationale: Hydrolysis is the term used to describe the breakdown of large molecules into smaller units by adding water. In the case of glycogen being broken down into glucose subunits, this process involves the addition of water molecules to break the glycosidic bonds between glucose molecules, resulting in the release of individual glucose subunits. This process is crucial for providing cells with a source of energy when needed. Choice B, Reduction, refers to a chemical reaction involving a gain of electrons or a decrease in oxidation state, not the breakdown of glycogen into glucose subunits. Choice C, Metabolism, is a broad term encompassing all biochemical processes in an organism, including anabolism and catabolism, but does not specifically describe the breakdown of glycogen into glucose subunits. Choice D, Transpiration, is the process of water movement through a plant and is not related to the breakdown of glycogen into glucose subunits.

3. Why is the nucleus important in a cell?

A. It stores the DNA
B. It supports the cell
C. It makes protein
D. It makes energy out of food

Correct answer: A

Rationale: The nucleus is important in a cell because it stores the DNA, which contains the genetic information necessary for the cell's function and replication. This genetic material controls the cell's activities and characteristics. Choices B, C, and D are incorrect because supporting the cell, making proteins, and producing energy are functions typically associated with other cell organelles like the cytoskeleton, ribosomes, and mitochondria, respectively.

4. Which of the following is a protein?

A. cellulose
B. hemoglobin
C. estrogen
D. ATP

Correct answer: B

Rationale: The correct answer is 'hemoglobin' because it is a protein that carries oxygen in the blood. Cellulose is a carbohydrate found in the cell walls of plants, not a protein. Estrogen is a hormone, not a protein. ATP (adenosine triphosphate) is a molecule that carries energy within cells, not a protein.

5. What type of tissue is fat?

A. Connective
B. Muscle
C. Nervous
D. Epithelial

Correct answer: A

Rationale: Fat is a type of loose connective tissue known as adipose tissue. Adipose tissue primarily functions to store energy and provide cushioning and insulation for organs. While muscle tissue is responsible for movement, nervous tissue transmits nerve impulses, and epithelial tissue covers and protects body surfaces, fat specifically falls under the category of connective tissue.