Nursing Elites

1. Which of the following enzymes unwinds the double-stranded DNA during replication?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.

2. Which of the following is NOT a major function of the respiratory system in humans?

• A. It provides a large surface area for gas exchange of oxygen and carbon dioxide.
• B. It helps regulate the blood's pH.
• C. It helps cushion the heart against jarring motions.
• D. It is responsible for vocalization.

Correct answer: C

Rationale: Option C, 'It helps cushion the heart against jarring motions,' is NOT a major function of the respiratory system in humans. The primary functions of the respiratory system include gas exchange, regulation of blood pH, and vocalization. The respiratory system does not play a role in cushioning the heart; that function is primarily carried out by the pericardium and other protective structures around the heart. Choices A, B, and D are major functions of the respiratory system in humans. Choice A refers to the respiratory system's role in gas exchange, Choice B highlights its involvement in regulating blood pH, and Choice D points out its responsibility for vocalization.

3. Which of the following terms refers to a muscle twitch, a single forceful contraction of a muscle fiber?

• A. Tetanus
• B. Tremor
• C. Fasciculation
• D. Rigidity

Correct answer: C

Rationale: The correct term for a muscle twitch, a single forceful contraction of a muscle fiber, is 'Fasciculation' (choice C). Fasciculation specifically describes this phenomenon. 'Tetanus' (choice A) refers to sustained muscle contraction, 'Tremor' (choice B) indicates a shaky or quivering movement, and 'Rigidity' (choice D) denotes stiffness or inflexibility in muscles. Therefore, choices A, B, and D are incorrect in the context of a single forceful contraction of a muscle fiber.

4. What is the muscular tube that transports sperm from the testes to the urethra called?

• A. Epididymis
• B. Vas deferens
• C. Seminal vesicle
• D. Cowper's gland

Correct answer: B

Rationale: The correct answer is the vas deferens. It is the muscular tube responsible for carrying sperm from the testes to the urethra. After sperm is produced in the testes, it moves to the epididymis for maturation and storage. The seminal vesicle contributes fluid to semen, but it is not the tube that transports sperm. Cowper's gland also adds fluid to semen but is not involved in transporting sperm. Therefore, the vas deferens is the accurate choice for the muscular tube that transports sperm.

5. What is the main target organ for insulin, the hormone produced by the pancreas?

• A. Liver
• B. Kidneys
• C. Muscles
• D. Brain

Correct answer: C

Rationale: The main target organ for insulin is muscles. Insulin plays a crucial role in regulating glucose metabolism by promoting the uptake of glucose into muscle cells. This glucose can then be utilized for energy production or stored for later use. Therefore, muscles are the primary site where insulin exerts its effects on glucose uptake and utilization. The liver primarily responds to insulin by regulating glucose storage and release, but the main target for insulin-mediated glucose uptake is muscles. Kidneys are not a target organ for insulin action in glucose metabolism. The brain does not heavily rely on insulin for glucose uptake as it primarily uses glucose independently of insulin for energy production.

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