HESI A2 Biology Practice Test

Correct Answer: A

Rationale: The correct answer is A: Bacteria. Eukaryotic cells have a defined nucleus and membrane-bound organelles, which bacteria lack. Dogs, humans, and onions are all multicellular organisms that possess eukaryotic cells. Bacteria, being prokaryotic, do not have a distinct nucleus or membrane-bound organelles, leading to the conclusion that they do not have eukaryotic cells.

Correct Answer: B

Rationale: The correct answer is B: smooth ER. The smooth ER is responsible for detoxifying multiple molecules through processes like drug metabolism and lipid synthesis. It contains enzymes that help break down toxins. The rough ER is primarily involved in protein synthesis, so it is not directly related to detoxification. Lysosomes are involved in breaking down cellular waste and are not specialized for detoxification. The Golgi apparatus is responsible for packaging and modifying proteins for transport, not detoxifying molecules. Therefore, the smooth ER is the most suitable organelle for detoxifying multiple molecules in a cell.

Correct Answer: D

Rationale: The correct answer is D because in DNA, adenine (A) always pairs with thymine (T), forming two hydrogen bonds. This is known as complementary base pairing, essential for DNA replication and maintenance. Options A, B, and C are incorrect as they do not demonstrate the complementary base pairing rule observed in DNA. Option A (A and G) is incorrect because adenine pairs with thymine, not guanine. Option B (A and C) is incorrect because adenine pairs with thymine, not cytosine. Option C (A and A) is incorrect because in DNA, adenine always pairs with thymine, not with itself.

Correct Answer: A

Rationale: Epithelial tissue is primarily found lining the organs, such as the skin, digestive tract, and respiratory tract. This tissue serves as a protective barrier and aids in absorption and secretion. The other choices, heart muscle, tendons, and spinal cord, are not locations where epithelial tissue is typically found. Heart muscle is cardiac muscle tissue, tendons are composed of dense regular connective tissue, and the spinal cord consists of nervous tissue. Therefore, the correct answer is A, organ lining, as it aligns with the typical locations of epithelial tissue in the body.

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.