ATI TEAS Practice Science Test

Correct Answer: B

Rationale: The correct answer is B: Cytoplasm. Pyruvate is an intermediate product of glycolysis, which occurs in the cytoplasm of the cell. The biochemist isolating pyruvate is working with the cytoplasm because that's where glycolysis takes place. Chloroplasts (A) are involved in photosynthesis, not glycolysis. Mitochondria (C) are responsible for aerobic respiration, where pyruvate is eventually transported to. The nucleus (D) contains the cell's genetic material and is not directly involved in pyruvate metabolism. Thus, the biochemist is likely isolating pyruvate from the cytoplasm.

Correct Answer: A

Rationale: The hypodermis is primarily composed of adipose tissue, which is a type of connective tissue. Adipose tissue serves as a layer of insulation and energy storage in the body. It helps regulate body temperature and provides cushioning for organs. Adipose tissue is the main component of the hypodermis, making choice A the correct answer. Choices B, C, and D are incorrect because the hypodermis is not primarily composed of regular connective tissue, epithelial tissue, or muscle tissue.

Correct Answer: A

Rationale: The correct answer is A: They are small and soluble. Small molecules can easily diffuse across cell membranes, while soluble molecules can dissolve in the cell's aqueous environment. This combination allows the signals to pass through the membrane and bind to intracellular receptors. Choice B (large and soluble) is incorrect because large molecules have difficulty crossing the membrane. Choices C (small and insoluble) and D (large and insoluble) are incorrect as they do not facilitate the passage of signals across the cell membrane for binding to intracellular receptors.

Correct Answer: B

Rationale: The correct answer is B: The plant left outside in normal conditions serves as the control of the experiment. This is because the control group in an experiment remains unchanged and is used as a baseline for comparison. In this case, the plant left outside in normal conditions is the control as it is not subjected to any experimental manipulation, unlike the other tropical plants in the greenhouse. By comparing the growth of the plants in the greenhouse to the plant left outside, any changes in plant height can be attributed to the varying humidity levels, thus allowing for a valid comparison. Choice A is incorrect because plant height for each tropical plant is the experimental variable being measured, not the control. Choice C is incorrect as humidity level readings in the greenhouse are part of the experimental conditions, not the control. Choice D is incorrect because the amount of time used to study plant height is not the control of the experiment; it is the duration of the study.

Correct Answer: C

Rationale: The correct answer is C: Flexor. Flexor muscles are responsible for bending a joint by decreasing the angle between the bones they act upon. They contract to bring two body parts closer together. Cardiac muscles (A) are found in the heart and control its pumping action. Extension (B) refers to the straightening of a joint, not bending. Smooth muscles (D) are found in various organs and are not directly involved in joint movement. Therefore, the flexor muscle (C) is the correct choice for causing a joint to bend.