HESI A2 Biology Practice Test

Correct Answer: D

Rationale: The correct answer is D because all the choices - the pituitary gland, the thyroid gland, and the adrenal glands - are indeed components of the endocrine system. Each of these glands secretes hormones directly into the bloodstream to regulate various bodily functions. The pituitary gland controls other endocrine glands, the thyroid gland regulates metabolism, and the adrenal glands manage stress responses. Therefore, all of these glands play vital roles in the endocrine system. The other choices (A, B, C) are incorrect because they are all components of the endocrine system.

Correct Answer: A

Rationale: The correct answer is A: It controls the substances entering and leaving the cell. The cell membrane acts as a selective barrier, regulating the passage of molecules in and out of the cell. It does this through various mechanisms such as protein channels and pumps. This function is crucial for maintaining cellular homeostasis and ensuring the cell's survival. Summary: - B: It maintains the cell's shape: The cell membrane does contribute to the cell's shape but this is not its primary function. - C: It controls the substances entering the cell: This is partially correct, but the cell membrane also controls substances leaving the cell. - D: It supports the cell's structures: While the cell membrane provides some structural support, its main function is controlling the movement of substances.

Correct Answer: D

Rationale: Cytokinesis occurs to physically separate the two daughter cells after cell division. This process ensures that each daughter cell receives a complete set of organelles and genetic material. The correct answer, choice D, states that daughter cells can divide, which aligns with the purpose of cytokinesis. Choices A and B are incorrect as they do not directly relate to the process of cytokinesis. Choice C is also incorrect as cytokinesis is not primarily involved in killing bacteria, but rather in ensuring successful cell division.

Correct Answer: C

Rationale: Anaerobic respiration occurs in bacteria because they live in environments with low oxygen levels. Bacteria adapt to anaerobic conditions by utilizing alternative pathways to generate energy without oxygen. This process allows them to survive and thrive in oxygen-deprived environments. The other choices are incorrect because animals require oxygen for aerobic respiration, plants use sunlight for photosynthesis, and option D is incorrect as bacteria indeed undergo anaerobic respiration in low oxygen environments.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Diploid organisms can be multicellular or unicellular, so A is not universally true. 2. Diploid cells can be somatic or germ cells, so B is not always true. 3. Diploid cells always have two sets of homologous chromosomes, making C true. 4. Since C is true and A and B are not always true, the correct answer is D.