which is true of gametes

HESI A2

Biology HESI A2 Practice Test

1. Which is true of gametes?

A. They are diploid cells
B. They are haploid cells
C. They are somatic
D. A & C are true

Correct answer: B

Rationale: Gametes are sex cells (sperm and eggs) that are involved in sexual reproduction. They are haploid cells, meaning they have half the number of chromosomes (n) compared to diploid cells. This is necessary for the formation of a diploid zygote when two gametes unite during fertilization. Somatic cells are non-reproductive cells in the body, so they are not gametes. Choice A is incorrect because gametes are not diploid but haploid. Choice C is incorrect because gametes are not somatic cells.

2. Where is the slide typically placed on a microscope?

A. Eyepiece
B. Stage
C. Focus knob
D. Objective lens

Correct answer: B

Rationale: The slide is typically placed on the stage of a microscope. The stage is the platform where the slide containing the specimen is positioned for viewing. The eyepiece is where you look through to view the specimen, the focus knob is used to sharpen the image, and the objective lens is responsible for magnification. Therefore, the correct answer is the stage.

3. Which one of the following best describes the function of a cell membrane?

A. It controls the substances entering and leaving the cell.
B. It maintains the cell's shape.
C. It controls the substances entering the cell.
D. It supports the cell's structures.

Correct answer: A

Rationale: The correct answer is A. The function of a cell membrane is to control the substances entering and leaving the cell. The cell membrane is selectively permeable, allowing it to regulate the movement of ions and molecules in and out of the cell to maintain internal balance and proper function. Choice B is incorrect because while the cell membrane does provide some structural support, its primary function is not to maintain the cell's shape. Choice C is incorrect because the cell membrane controls both the substances entering and leaving the cell, not just those entering. Choice D is incorrect as the primary function of the cell membrane is not to support the cell's structures but to regulate the movement of substances.

4. What happens to glucose during glycolysis?

A. Its energy is entirely lost.
B. It splits into molecules of pyruvic acid.
C. It is stored in NADH.
D. It joins with molecules of citric acid.

Correct answer: B

Rationale: During glycolysis, glucose undergoes a series of enzymatic reactions in the cytoplasm of the cell, resulting in its breakdown into two molecules of pyruvic acid. This process also generates ATP and NADH as energy carriers. Choice A is incorrect because glucose is not entirely lost, but rather converted into other molecules. Choice C is incorrect because NADH is a product of glycolysis, not a storage form for glucose. Choice D is incorrect as glucose does not join with molecules of citric acid during glycolysis, but rather in subsequent stages of cellular respiration.

5. The apical side of an epithelial cell:

A. Is exposed to fluid or air
B. Is on the bottom side of the cell
C. Does not allow any substances to pass through
D. None of the above

Correct answer: A

Rationale: The apical side of an epithelial cell is the top side, which is typically exposed to fluids, air, or the inside of an organ. This side allows substances to pass through it, facilitating the absorption, secretion, or excretion of various substances. Choice B is incorrect as the apical side is not on the bottom but the top side. Choice C is incorrect as the apical side does allow substances to pass through. Choice D is incorrect as there are characteristics associated with the apical side.