HESI A2 Practice Test Biology

Correct Answer: C

Rationale: The correct answer is C, fermentation and cellular respiration, because both are catabolic pathways that lead to cellular energy production. Fermentation occurs in the absence of oxygen, producing a small amount of ATP. Cellular respiration, on the other hand, occurs in the presence of oxygen and is a more efficient process, producing a significantly higher amount of ATP. Choices A, B, and D are incorrect because internal respiration, external respiration, and anaerobic respiration do not directly lead to cellular energy production through catabolic pathways.

Correct Answer: B

Rationale: The correct answer is B: Sexual reproduction and asexual reproduction. Sexual reproduction involves the fusion of gametes from two parents to create offspring with genetic variation. Asexual reproduction involves a single parent producing genetically identical offspring. Option A is incorrect because binary fission is a form of asexual reproduction, not sexual reproduction. Option C is incorrect because binary fission is a specific type of asexual reproduction, not the only category. Option D is incorrect because mitosis is a cell division process within asexual reproduction, but it is not a category of cell reproduction on its own.

Correct Answer: B

Rationale: The correct answer is B: hemoglobin. Hemoglobin is a protein because it is composed of amino acids linked together in a specific sequence to form a complex structure that carries oxygen in red blood cells. Cellulose (choice A) is a carbohydrate, estrogen (choice C) is a hormone, and ATP (choice D) is a nucleotide that serves as a source of energy in cells. Hemoglobin's role in oxygen transport and its structural composition as a sequence of amino acids classify it as a protein.

Correct Answer: C

Rationale: The correct answer is C: Supply electrons in the light reactions. In photosynthesis, water molecules are split during the light reactions of photosynthesis, releasing electrons that are used to drive the electron transport chain. This process generates ATP and NADPH, which are essential for the synthesis of glucose in the Calvin cycle. Water does not combine with carbon dioxide (A), absorb light energy (B), or transport hydrogen ions in the dark reactions (D) during photosynthesis.

Correct Answer: A

Rationale: The correct answer is A: Phospholipids. Phospholipids are essential components of the plasma membrane due to their amphipathic nature, with hydrophilic heads and hydrophobic tails. This structure allows phospholipids to form a lipid bilayer, creating a barrier that separates the internal and external environments of the cell. Steroids (B) are not a major component of the plasma membrane. Sugars (C) are found in glycoproteins and glycolipids on the membrane surface, but they are not the main structural component. Amino acids (D) are the building blocks of proteins, which can be membrane proteins, but they are not the key structural component of the membrane itself.