Nursing Elites

1. Which of the following compounds often contains a carboxyl group?

• A. Carbohydrates
• B. Glycolipids
• C. Amino Acids
• D. DNA

Correct answer: C

Rationale: The correct answer is C: Amino Acids. Amino acids, the building blocks of proteins, contain both an amine group and a carboxyl group. The carboxyl group (-COOH) is crucial for the structure and function of proteins as it participates in peptide bond formation. Carbohydrates and DNA do not typically contain carboxyl groups as a functional group. Glycolipids consist of a carbohydrate chain linked to a lipid, but they do not inherently contain a carboxyl group.

2. Which hormone, produced by the thyroid gland, plays a key role in regulating calcium levels in the blood by promoting calcium release from bones and increasing calcium reabsorption in the kidneys?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: A

Rationale: Calcitonin, produced by the thyroid gland, is responsible for regulating calcium levels in the blood. It works by decreasing blood calcium levels through two main mechanisms: promoting calcium uptake by bones and decreasing calcium reabsorption in the kidneys. Parathyroid hormone (PTH), on the other hand, increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines. Thyroxine, another thyroid hormone, primarily regulates metabolism and has no direct influence on calcium levels. Insulin, produced by the pancreas, is involved in regulating blood sugar levels and is not related to calcium homeostasis.

3. Which protein complex in the sarcomere is responsible for the thick filament?

• A. Actin
• B. Myosin
• C. Tropomyosin
• D. Troponin

Correct answer: B

Rationale: Myosin is the protein complex responsible for the thick filament in the sarcomere. It interacts with actin, another protein in the sarcomere, to generate the sliding movement that results in muscle contraction. Actin is a thin filament protein that interacts with myosin to create the sliding filament mechanism. Tropomyosin and troponin are regulatory proteins that regulate muscle contraction by controlling the interaction between actin and myosin, rather than directly being responsible for the thick filament.

4. What causes stretch marks?

• A. The epidermis layer becomes inflamed
• B. The dermis layer becomes inflamed
• C. The dermis layer tears due to rapid stretching
• D. Sebaceous glands become clogged

Correct answer: C

Rationale: Stretch marks occur when the dermis layer tears due to rapid stretching of the skin. This tearing leads to the appearance of stretch marks, which are often red or purple at first and then fade to a silvery-white color over time. Inflammation of the dermis or clogging of sebaceous glands are not directly related to the formation of stretch marks. Therefore, choices A, B, and D are incorrect as they do not describe the actual cause of stretch marks.

5. What is a characteristic feature of a convex lens?

• A. Converge light rays
• B. Diverge light rays
• C. Focus sound waves
• D. Create virtual images only

Correct answer: A

Rationale: A convex lens is characterized by its ability to converge light rays. The convex lens is thicker in the middle and thinner at the edges, causing light rays passing through it to converge or come together at a focal point on the opposite side of the lens. This convergence of light rays is what distinguishes convex lenses. Choice B is incorrect as convex lenses do not diverge light rays. Choice C is incorrect as convex lenses do not focus sound waves but rather light waves. Choice D is incorrect as convex lenses can create both real and virtual images, not just virtual images.

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