Biology HESI A2 Practice Test

Correct Answer: A

Rationale: The correct answer is A because the apical side of an epithelial cell is the top surface that is exposed to fluid or air. This surface is specialized for absorption, secretion, and protection. Choice B is incorrect because the apical side is actually the top side of the cell, not the bottom. Choice C is incorrect because the apical side allows substances to pass through via various transport mechanisms such as active transport, facilitated diffusion, or simple diffusion. Choice D is incorrect because the apical side of an epithelial cell is indeed exposed to fluid or air, making it the correct answer.

Correct Answer: D

Rationale: The correct answer is D because optical microscopy utilizes visible light (B) to observe samples. This method does not use scanning electrons (A) as in electron microscopy. While some optical microscopes may use dyes (C), it is not a defining characteristic. Therefore, D is correct as it acknowledges both the use of visible light and the potential use of dyes in optical microscopy.

Correct Answer: D

Rationale: Homeostasis is necessary to maintain stable internal conditions in the body for optimal function. A: Temperature regulation ensures enzymes work efficiently. B: pH balance is crucial for enzyme activity and cell function. C: Glucose levels impact energy production. D: All choices are essential for overall health and function, making D the correct answer. Maintaining just one aspect wouldn't be enough to support the body's complex processes.

Correct Answer: B

Rationale: The correct answer is B because the Krebs cycle involves the oxidation of acetyl CoA, a product of glycolysis, leading to the production of NADH and FADH2. Choice A is incorrect because the proteins are not directly involved in the Krebs cycle. Choice C is incorrect because protons are not passed along a gradient in the Krebs cycle; they are used in the electron transport chain to produce ATP. Choice D is incorrect because the Krebs cycle is not known as the glycolic acid cycle; glycolysis is the pathway that produces glycolic acid.

Correct Answer: C

Rationale: The correct answer is C: Cells can convert nutrients to energy. Cellular respiration is the process by which cells break down nutrients to produce energy in the form of ATP. This energy is essential for various cellular functions. Choice A is incorrect because DNA replication is a separate process. Choice B is incorrect as cellular respiration is not related to breathing, which is the exchange of gases. Choice D is incorrect as cell division is a different cellular process called mitosis or meiosis.