Nursing Elites

1. What macromolecules are proteins that speed up chemical reactions and act as biological catalysts?

• A. Lipids
• B. Enzymes
• C. Carbohydrates
• D. Nucleic acids

Correct answer: B

Rationale: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions without being consumed in the process. Lipids, carbohydrates, and nucleic acids do not serve as proteins that function as catalysts; they have different biological roles. Lipids are primarily used for energy storage, structural components, and signaling molecules. Carbohydrates are mainly for energy storage and providing structural support. Nucleic acids are involved in genetic information storage and transfer. Therefore, the correct answer is B: Enzymes.

2. Mesosomes are the internal extensions of which of the following?

• A. Capsule
• B. Cell membranes
• C. Cell wall
• D. Chromatin body

Correct answer: B

Rationale: Mesosomes are the internal extensions of the cell membrane, not the capsule, cell wall, or chromatin body. They play a crucial role in cell division and are essential for various cellular processes such as respiration and cell wall formation. Mesosomes are not associated with the capsule (choice A), cell wall (choice C), or chromatin body (choice D), making these options incorrect.

3. What is the function of the endocrine system?

• A. To protect the body from infection
• B. To release digestive enzymes
• C. To break down food
• D. To regulate the sleep-wake cycle

Correct answer: B

Rationale: The correct answer is B. The endocrine system releases hormones that regulate various functions, including metabolism and growth. It is responsible for producing and releasing hormones that control processes such as metabolism, growth, and development. The digestive enzymes are released by the digestive system, not the endocrine system. Choices A, C, and D are incorrect because protecting the body from infection is primarily the role of the immune system, breaking down food is the function of the digestive system, and regulating the sleep-wake cycle is controlled by the circadian rhythm which is mainly influenced by the brain's hypothalamus and not the endocrine system.

4. The 'fight-or-flight' response is triggered by the hormone released from the:

• A. Thyroid gland
• B. Adrenal glands
• C. Pituitary gland
• D. Pancreas

Correct answer: B

Rationale: The 'fight-or-flight' response is triggered by the release of adrenaline (epinephrine) and norepinephrine from the adrenal glands. These hormones prepare the body to either confront or flee from a perceived threat or stressor. The adrenal glands are crucial in initiating this rapid physiological response. Choices A, C, and D are incorrect because the thyroid gland primarily regulates metabolism and energy levels, the pituitary gland controls other endocrine glands but does not directly trigger the 'fight-or-flight' response, and the pancreas is responsible for regulating blood sugar levels through insulin and glucagon, not for triggering the 'fight-or-flight' response.

5. Which of the following is specialized tissue in the right atrium that acts as the heart’s natural pacemaker by generating the electrical signal for the heartbeat?

• A. sinus venosus
• B. sinoatrial node
• C. atrioventricular node
• D. tricuspid valve

Correct answer: B

Rationale: The sinoatrial node, often referred to as the SA node, is specialized tissue located in the right atrium of the heart. It functions as the heart's natural pacemaker by generating the electrical signal that initiates each heartbeat. This electrical signal spreads to the atrial muscles and then to the atrioventricular node, causing the heart to contract rhythmically and efficiently. The other options listed do not serve as the heart's natural pacemaker responsible for generating the electrical signal for the heartbeat. Sinus venosus is a developmental structure in fetal hearts, the atrioventricular node delays the electrical signal, and the tricuspid valve is a heart valve that prevents backflow of blood from the right ventricle to the right atrium.

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