HESI A2 Biology Practice Test

Correct Answer: A

Rationale: The correct answer is A: It controls the substances entering and leaving the cell. The cell membrane acts as a selective barrier, regulating the passage of molecules in and out of the cell. It does this through various mechanisms such as protein channels and pumps. This function is crucial for maintaining cellular homeostasis and ensuring the cell's survival. Summary: - B: It maintains the cell's shape: The cell membrane does contribute to the cell's shape but this is not its primary function. - C: It controls the substances entering the cell: This is partially correct, but the cell membrane also controls substances leaving the cell. - D: It supports the cell's structures: While the cell membrane provides some structural support, its main function is controlling the movement of substances.

Correct Answer: D

Rationale: The correct answer is D because it follows the structure of a hypothesis: it states a relationship between two variables (exposure to red light and plant growth) that can be tested. It is specific, testable, and predicts an outcome. Choice A is a general statement, not a testable hypothesis. Choice B is subjective and not testable. Choice C lacks specificity and does not clearly define the relationship being tested.

Correct Answer: D

Rationale: The correct answer is D: cellular respiration and fermentation. Cellular respiration is the process by which cells convert glucose and oxygen into ATP, providing energy for the cell. Fermentation is an anaerobic process that also produces ATP but does not require oxygen. Both pathways are catabolic, breaking down molecules to release energy. Option A is incorrect because protein synthesis is an anabolic process that builds proteins and does not directly produce energy. Option B is incorrect because cellular respiration and glycolysis are both energy-producing pathways, not protein synthesis. Option C is incorrect because it includes fermentation and glycolysis, omitting cellular respiration, which is a major pathway for energy production in cells.

Correct Answer: D

Rationale: The correct answer is D: They are denoted Aa. Heterozygous traits refer to the presence of different alleles at a specific gene locus. In this case, A and a represent two different alleles for the same trait. When an individual is heterozygous, one allele is dominant (A) and the other is recessive (a). Therefore, the correct notation for a heterozygous trait is Aa. Option A is incorrect because heterozygous traits are not haploid (having one set of chromosomes), but diploid (having two sets). Option B is incorrect as it denotes a homozygous dominant genotype. Option C is incorrect as it denotes a homozygous recessive genotype.

Correct Answer: B

Rationale: The correct answer is B: Prokaryotic cells have a capsule. This is because the capsule is a protective layer outside the cell wall that helps the prokaryotic cell adhere to surfaces and evade the immune system. Prokaryotic cells do not have a nucleus (choice A), membrane-bound organelles (choice C), or the ability to move on their own (choice D). The absence of a nucleus and membrane-bound organelles distinguishes prokaryotic cells from eukaryotic cells. Choice D is incorrect because prokaryotic cells can move using various mechanisms such as flagella or pili.