Biology HESI A2 Practice Test

Correct Answer: A

Rationale: The correct answer is A: TGAACGT. To find the matching DNA strand, we need to use complementary base pairing rules: A pairs with T, C pairs with G. Given the segment ACTTGCA, its complementary DNA strand would be TGAACTG. Therefore, the correct answer is A. Option B (GACCATG) is incorrect because it does not follow the complementary base pairing rules. Option C (ACTTGCA) is the same as the original segment given, so it is also incorrect. Option D (None of the above) is incorrect as the correct answer is A.

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: A

Rationale: The correct answer is A: Through a contractile ring. Animal cells divide through a process called cytokinesis, where a contractile ring made of actin and myosin filaments constricts the cell membrane, leading to cell division. This process is specific to animal cells. Choice B, via a cell plate, is characteristic of plant cells, not animal cells. Choice C, both methods, is incorrect as animal cells do not divide using a cell plate. Choice D, none of the above, is incorrect as animal cells do divide through a contractile ring.

Correct Answer: C

Rationale: The correct answer is C because both prokaryotic and eukaryotic cells possess a cell membrane. The cell membrane is a crucial structure present in all cells that separates the internal cellular environment from the external environment. In prokaryotic cells, the cell membrane is the outermost boundary, while in eukaryotic cells, it is surrounded by other membrane-bound organelles. Choice A is incorrect because prokaryotic cells lack membrane-bound organelles, but they still have a cell membrane. Choice B is incorrect because eukaryotic cells do possess a cell membrane. Choice D is incorrect as it contradicts the basic understanding of cell biology.

Correct Answer: A

Rationale: The correct answer is A: hypothesis. A hypothesis is a statement that proposes an explanation for a phenomenon based on available evidence. It helps guide scientific inquiry by providing a testable prediction. Observations (B) are simply data collected through senses. Experiments (C) involve testing hypotheses through controlled conditions. Conclusions (D) are interpretations drawn from the data collected. Therefore, a hypothesis is the initial statement or explanation of certain events or happenings in the scientific process.