Nursing Elites

1. What is the structure of DNA?

• A. Single-stranded, linear
• B. Double-stranded, linear
• C. Double-stranded, helix
• D. Single-stranded, helix

Correct answer: C

Rationale: The correct answer is C: Double-stranded, helix. DNA is structured as a double helix formed by two strands of nucleotides. The nucleotides are paired with complementary bases (A-T and C-G) in the center, held together by hydrogen bonds. This double-stranded helical structure is a fundamental characteristic of DNA and essential for its function in storing genetic information. Choices A, B, and D are incorrect because DNA is not single-stranded; it consists of two strands that run antiparallel to each other and are connected via hydrogen bonds. Additionally, DNA does not have a linear structure but rather a helical one, providing stability and protection to the genetic information it carries.

2. Cartilage is a flexible connective tissue found in the:

• A. Center of long bones
• B. Joints between bones
• C. Muscle tissue
• D. Walls of blood vessels

Correct answer: B

Rationale: Cartilage is a flexible connective tissue found in the joints between bones. It provides cushioning and support for the bones, allowing smooth movement and reducing friction between them. Cartilage acts as a shock absorber and helps maintain the structural integrity of the joints. Choices A, C, and D are incorrect because cartilage is not typically found in the center of long bones, muscle tissue, or the walls of blood vessels. Cartilage primarily functions in providing structural support and flexibility in joints.

3. Which of the following structures is responsible for producing insulin?

• A. Liver
• B. Pancreas
• C. Gallbladder
• D. Spleen

Correct answer: B

Rationale: The correct answer is B: Pancreas. The pancreas is the organ responsible for producing insulin. Insulin is a hormone that helps regulate blood sugar levels by allowing cells to take in glucose from the bloodstream. The liver (choice A) plays a role in regulating blood sugar levels through glycogen storage and release but does not produce insulin. The gallbladder (choice C) stores bile produced by the liver to aid in digestion and has no direct involvement in insulin production. The spleen (choice D) is involved in immune function and blood storage but not in the production of insulin.

4. Which structure in the respiratory system is responsible for gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchi
• D. Diaphragm

Correct answer: B

Rationale: The alveoli in the lungs are responsible for gas exchange. Alveoli have a rich blood supply and thin walls, enabling the exchange of oxygen and carbon dioxide. Oxygen diffuses into the blood from the alveoli, while carbon dioxide diffuses out. The trachea functions as an air passage, bronchi are the main airways into the lungs, and the diaphragm is the primary muscle involved in breathing by aiding in lung expansion and contraction, but they are not directly responsible for gas exchange like the alveoli.

5. Which enzyme breaks down carbohydrates like starches and sugars in the mouth?

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

Correct answer: C

Rationale: The correct answer is Amylase. Amylase is the enzyme responsible for breaking down carbohydrates like starches and sugars in the mouth. Pepsin is a digestive enzyme that breaks down proteins in the stomach, lipase breaks down fats, and trypsin is another enzyme that breaks down proteins in the small intestine. Therefore, choices A, B, and D are incorrect for this question.

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