HESI A2 Biology Practice Test

Correct Answer: D

Rationale: The correct answer is D because phenotype is the observable characteristics resulting from the interaction between genotype, epigenetic factors, and environmental factors. Genotype (genetic makeup) provides the foundation, epigenetic factors can modify gene expression, and environmental factors play a crucial role in shaping the final phenotype. Explanation: A: Incorrect. Phenotype is not the genetic code itself but the physical expression of genetic traits. B: Incorrect. Phenotype does not determine genotype; genotype determines phenotype. C: Incorrect. Genotype determines phenotype, not the other way around. D: Correct. Genotype, epigenetic factors, and environmental factors collectively determine the phenotype, making it the most comprehensive and accurate choice.

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: B

Rationale: Enzymes are typically proteins because they are biological catalysts made up of amino acids. Proteins have specific structures that allow them to bind to substrates and speed up chemical reactions. Fats, sugars, and neurons do not possess the specific structural properties required for enzyme function. Therefore, the correct answer is B (Proteins).

Correct Answer: D

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: C

Rationale: The correct answer is C: The renal system. The renal system consists of the kidneys, ureters, bladder, and urethra, all of which are involved in the formation and release of urine. The kidneys filter waste products from the blood, and the ureters transport urine from the kidneys to the bladder. The bladder stores urine before it is eliminated through the urethra. Choice A, the digestive system, is incorrect because it primarily involves the organs responsible for digestion and absorption of nutrients, such as the stomach, intestines, and liver. Choice B, the reproductive system, is incorrect because it includes organs like the ovaries, testes, and uterus, involved in reproduction, not urine formation. Choice D, the kidney system, is incorrect as it is not a commonly used term to describe the collective organs involved in urine formation and excretion.