Biology HESI A2 Practice Test

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: Correct Answer: C Rationale: 1. Sexual reproduction involves two cells (sperm and egg) contributing genetic material to offspring, leading to genetic variation. 2. Greater genetic variation in offspring helps in adapting to changing environments and enhances species survival. 3. Asexual reproduction involves a single parent cell dividing to produce genetically identical offspring. 4. Option A is incorrect as sexual reproduction does not result in half of the cells being identical to the original cell. 5. Option B is incorrect as asexual reproduction does not result in greater variation, it produces genetically identical offspring. 6. Option D is incorrect as sexual reproduction involves two cells contributing genetic material, leading to variation.

Correct Answer: A

Rationale: The correct answer is A: Atmosphere. The atmosphere is the layer of gases that surrounds a planet. It consists of different layers, including the stratosphere and troposphere mentioned in the other choices. The biosphere refers to the regions on Earth where living organisms exist, not the gases surrounding the planet. Therefore, the correct term for the mixture of gases surrounding a planet is the atmosphere.

Correct Answer: C

Rationale: The correct answer is C because molecules move from areas of high concentration to low concentration through a process called passive diffusion, which does not require energy. This movement occurs to reach equilibrium. Choice A is incorrect as some molecules can pass through cell membranes using channels or transporters. Choice B is incorrect because molecules move from high to low concentration in passive transport. Choice D is incorrect because molecules are constantly moving due to various forces.

Correct Answer: B

Rationale: The correct answer is B: Tendons, ligaments. Tendons connect muscles to bones, enabling movement. Ligaments connect bones to each other, providing stability. Muscles and ligaments are not directly involved in connecting muscles to bones. Therefore, option B is the most appropriate choice.