Nursing Elites

1. What is the small repeating unit in the contractile apparatus of skeletal muscle?

• A. Myofibril
• B. Actin
• C. Sarcomere
• D. Myosin

Correct answer: C

Rationale: The correct answer is 'Sarcomere.' The sarcomere is the smallest repeating unit within myofibrils and is responsible for muscle contraction in skeletal muscle. It consists of overlapping actin and myosin filaments arranged in a highly organized structure that allows for the sliding of filaments during muscle contraction. 'Myofibril' (choice A) is incorrect because it is a larger structure composed of sarcomeres. 'Actin' (choice B) and 'Myosin' (choice D) are incorrect as they are individual proteins that are components of the sarcomere, not the smallest repeating unit itself.

2. What is the stage of mitosis during which the nuclear envelope reforms?

• A. Prophase
• B. Metaphase
• C. Telophase
• D. Cytokinesis

Correct answer: C

Rationale: During telophase, the nuclear envelope reforms around the separated sister chromatids at opposite poles of the cell. This stage marks the reversal of the processes that occurred during prophase, where the nuclear envelope breaks down. Metaphase is characterized by the alignment of chromosomes along the metaphase plate in the cell's center. Cytokinesis is the final step of cell division involving cytoplasmic division to form two daughter cells, but it does not involve the reformation of the nuclear envelope. Therefore, choice C (Telophase) is the correct answer as it specifically involves the reformation of the nuclear envelope, distinguishing it from the other stages of mitosis.

3. Which deadly disease was eliminated through an intensive vaccination program?

• A. AIDS
• B. Smallpox
• C. Diabetes type 1
• D. Rheumatoid arthritis

Correct answer: B

Rationale: Smallpox was eradicated globally through an intensive vaccination program. The World Health Organization (WHO) led a successful global campaign to vaccinate people against smallpox, ultimately leading to its eradication in 1980. AIDS, diabetes type 1, and rheumatoid arthritis are serious conditions, but they were not eliminated through vaccination programs like smallpox. Therefore, the correct answer is B, Smallpox. AIDS is caused by the human immunodeficiency virus (HIV) and remains a significant global health issue. Diabetes type 1 is an autoimmune condition where the body attacks insulin-producing cells, leading to high blood sugar levels. Rheumatoid arthritis is an autoimmune condition that primarily affects the joints, causing inflammation and pain.

4. Which element is found in water and is crucial for biological functions like nerve impulses and muscle contraction?

• A. Sodium
• B. Potassium
• C. Calcium
• D. Magnesium

Correct answer: A

Rationale: The correct answer is Sodium. Sodium is found in water and is crucial for biological functions like nerve impulses and muscle contraction. It plays a key role in maintaining electrolyte balance and transmitting nerve impulses, affecting both muscles and nerves. Potassium (Choice B), although essential for nerve function and muscle control, is not typically found in water. Calcium (Choice C) is important for bone health and muscle function, but it is not the element found in water. Magnesium (Choice D) is also essential for various biological functions but is not the element commonly found in water.

5. Which digestive enzyme is primarily responsible for breaking down proteins?

• A. Pepsin
• B. Lipase
• C. Amylase
• D. Maltase

Correct answer: A

Rationale: The correct answer is A, Pepsin. Pepsin is primarily responsible for breaking down proteins in the stomach. It is produced in an inactive form called pepsinogen, which becomes activated by the acidic environment in the stomach. Pepsin functions by breaking down proteins into smaller peptides, which are further digested by other enzymes in the small intestine. Lipase is responsible for breaking down fats, amylase for carbohydrates, and maltase for converting maltose into glucose. Therefore, choices B, C, and D are incorrect as they are associated with breaking down fats, carbohydrates, and converting maltose, respectively, not proteins.

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