HESI A2 Biology Practice Test

Correct Answer: C

Rationale: Anaerobic respiration occurs in bacteria because they live in environments with low oxygen levels. Bacteria adapt to anaerobic conditions by utilizing alternative pathways to generate energy without oxygen. This process allows them to survive and thrive in oxygen-deprived environments. The other choices are incorrect because animals require oxygen for aerobic respiration, plants use sunlight for photosynthesis, and option D is incorrect as bacteria indeed undergo anaerobic respiration in low oxygen environments.

Correct Answer: B

Rationale: The correct answer is B because of osmosis. Saltwater has a higher concentration of solute than the egg, causing water to move out of the egg, leading to shrinkage. A is incorrect as the egg will lose water, not expand. C is incorrect as there will be a change due to osmosis. D is incorrect as an effect will occur.

Correct Answer: B

Rationale: The correct answer is B: Carrier proteins. Carrier proteins change shape to facilitate the movement of specific molecules across the membrane. They bind to the target molecule on one side of the membrane, undergo a conformational change, and release the molecule on the other side. This process is selective and energy-dependent. Option A (Diffusion) is incorrect because diffusion is a passive process that does not involve proteins changing shape to transport molecules. Option C (Channel proteins) is incorrect because channel proteins provide a passageway for specific molecules to move across the membrane but do not change shape to transport molecules. Option D (None of the above) is incorrect because carrier proteins specifically fit the description provided in the question.

Correct Answer: A

Rationale: The correct answer is A because water is a raw material for the light reactions in photosynthesis, specifically in the process of photolysis where water is split to release electrons for the photosystems. Without enough water, this process is hindered, leading to a drop in photosynthetic rate. Choice B is incorrect because carbon dioxide availability affects the Calvin cycle, not the light reactions. Choice C is incorrect as carbon atoms for sugar come from carbon dioxide, not water. Choice D is incorrect because fermentation is not directly related to the availability of water in photosynthesis.

Correct Answer: A

Rationale: The correct answer is A: Connective tissue. Fat is a type of adipose tissue, which is a specialized form of connective tissue that stores energy in the form of fat cells. Connective tissue provides support, structure, and insulation to the body. Muscle tissue (B) is responsible for movement, nervous tissue (C) transmits signals, and epithelial tissue (D) forms protective barriers. Fat does not perform these functions, hence choices B, C, and D are incorrect.