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: The correct answer is C: epididymis. The epididymis is the structure in the male reproductive system that stores spermatozoa during the maturation process. Sperm are produced in the testes and then move to the epididymis for storage and maturation before being ejaculated. The vas deferens is the tube that carries mature sperm from the epididymis to the urethra during ejaculation. The scrotum is the external sac that holds the testes and helps regulate their temperature. The testicular artery supplies blood to the testes but is not directly involved in storing spermatozoa.

Correct Answer: C

Rationale: The correct answer is C: Prophase, prometaphase, metaphase, anaphase, and telophase. 1. Prophase: Chromosomes condense and become visible. 2. Prometaphase: Nuclear envelope breaks down, spindle fibers attach to chromosomes. 3. Metaphase: Chromosomes line up at the metaphase plate. 4. Anaphase: Sister chromatids separate and move towards opposite poles. 5. Telophase: Chromatids reach poles, nuclear envelope reforms. Other choices are incorrect because they either include incorrect phases (A, B) or repeat phases (D).

Correct Answer: B

Rationale: The scientist needs 12mL, which is equivalent to 0.012L. Since the bottle holds 12L, it contains more than enough solution. Therefore, choice B is correct. Choice A is incorrect because the scientist needs less than the total amount in the bottle. Choice C is incorrect because the scientist actually has more than enough. Choice D is also incorrect as the scientist does have more than required.

Correct Answer: A

Rationale: Adenine is a purine base because it has a double-ring structure, which is a characteristic of purines. It pairs with thymine in DNA and uracil in RNA. Cytosine, thymine, and guanine are pyrimidines, which have a single-ring structure. Therefore, the correct answer is A. Cytosine, thymine, and guanine are incorrect choices as they are pyrimidines.