macromolecules are built of

ATI RN

ATI Anatomy and Physiology Online Practice

1. Macromolecules are built of?

A. Monomers
B. Incorrect
C. Not Applicable
D. None of the above

Correct answer: A

Rationale: The correct answer is A: Monomers. Macromolecules are built from smaller subunits called monomers. Monomers join together through chemical reactions to form larger molecules known as macromolecules. Option B is incorrect as it does not provide the accurate information regarding the composition of macromolecules. Option C is not applicable as it does not offer a relevant choice. Option D is incorrect because there is a specific answer related to the composition of macromolecules.

2. A parietal layer of a serous membrane lines cavities, whereas a visceral layer of a serous membrane covers organs.

A. covers organs; lines cavities
B. lines cavities; covers organs
C. secretes serous fluid; secretes mucus
D. secretes mucus; secretes a serous fluid

Correct answer: B

Rationale: In serous membranes, the parietal layer lines the cavities, providing support and protection, while the visceral layer covers the organs, reducing friction and allowing them to move freely. Therefore, the correct answer is 'lines cavities; covers organs.' Choices C and D are incorrect because serous membranes do not secrete mucus; instead, they secrete a watery serous fluid. Choice A is incorrect as it reverses the functions of the parietal and visceral layers in relation to organs and cavities.

3. Calcium concentration in the blood is controlled by which of the following glands?

A. Hypothalamus gland
B. Thyroid gland
C. Pituitary gland
D. Parathyroid glands

Correct answer: D

Rationale: The correct answer is Parathyroid glands. The parathyroid glands are responsible for regulating calcium levels in the blood by secreting parathyroid hormone (PTH). PTH helps increase calcium levels in the blood when they are too low. The other glands listed, such as the Hypothalamus, Thyroid, and Pituitary glands, do not directly control calcium concentration in the blood.

4. What causes wrinkled and sagging skin?

A. Drinking too much water
B. Heredity alone
C. Loss of subcutaneous fat and reduced levels of elastin and collagen
D. Excess subcutaneous fat

Correct answer: C

Rationale: Wrinkled and sagging skin is primarily caused by the loss of subcutaneous fat and reduced levels of elastin and collagen in the skin. Choice A is incorrect as drinking too much water does not lead to wrinkled and sagging skin. Choice B is incorrect because heredity alone does not cause this condition. Excess subcutaneous fat, as mentioned in Choice D, can contribute to a different skin appearance, such as puffiness, but not wrinkled and sagging skin.

5. Is the elbow distal to the wrist?

A. TRUE
B. FALSE
C. Not Sure
D. None of the above

Correct answer: B

Rationale: The correct answer is False. In anatomical terms, 'distal' means farther away from the center of the body or the point of attachment. The elbow is proximal to the wrist because it is closer to the center of the body. Therefore, the statement that the elbow is distal to the wrist is incorrect. Choice A is incorrect because the elbow is not distal to the wrist. Choice C is incorrect as the anatomical relationship between the elbow and wrist can be determined. Choice D is incorrect as there is a definitive answer to this anatomical question.