the correct answer is d heterozygous traits contain one dominant and one recessive form of the gene which of the following is true of homozygous trait

HESI A2

Biology HESI A2 Practice Test

1. Which of the following is true of homozygous traits?

A. They are haploid
B. They are denoted AA
C. They are denoted aa
D. They are denoted Aa

Correct answer: B

Rationale: Homozygous traits have two identical forms of the gene, either both dominant (AA) or both recessive (aa). Therefore, choices B and C are true for homozygous traits. Choice A is incorrect because being haploid refers to having a single set of chromosomes, not necessarily homozygous traits. Choice D is incorrect as homozygous traits have identical alleles, so they are not denoted as Aa.

2. How are lipids different from other organic molecules?

A. They are indivisible.
B. They are not water soluble.
C. They contain zinc.
D. They form long proteins.

Correct answer: B

Rationale: The correct answer is B: 'They are not water soluble.' Lipids are not water-soluble, which distinguishes them from other organic molecules. Choice A is incorrect because lipids are not indivisible; they can be broken down into fatty acids and glycerol. Choice C is incorrect as lipids do not necessarily contain zinc; they are a diverse group of molecules. Choice D is incorrect because lipids do not form long proteins; proteins are made up of amino acids, not lipids.

3. What takes place in a lysosome?

A. Ribosomes are made.
B. Food is produced.
C. Water is stored.
D. Food is digested.

Correct answer: D

Rationale: In a lysosome, food particles are digested through the action of enzymes. Lysosomes are membrane-bound organelles containing digestive enzymes that break down large molecules into smaller ones, allowing the cell to utilize the nutrients for energy and other processes. Choices A, B, and C are incorrect because ribosomes are not made in lysosomes, food is not produced in lysosomes, and lysosomes do not store water.

4. 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.

5. Why is DNA important for the metabolic activities of the cell?

A. It initiates cellular mitosis.
B. It provides cell wall stability.
C. It increases glucose absorption.
D. It controls the synthesis of enzymes.

Correct answer: D

Rationale: DNA is important for the metabolic activities of the cell because it controls the synthesis of enzymes. Enzymes are essential for catalyzing metabolic reactions in the cell. Choices A, B, and C are incorrect because DNA is not directly involved in cellular mitosis, cell wall stability, or glucose absorption.