Nursing Elites

1. Which of the following does not describe a general trait of macromolecules?

• A. They can exist as single chains.
• B. They can be branched.
• C. They all contain carbon, hydrogen, and phosphorus.
• D. They are all used by the body.

Correct answer: C

Rationale: The correct answer is C. While many macromolecules contain carbon, hydrogen, and phosphorus, not all of them do. For example, lipids, a type of macromolecule, may not contain phosphorus. Choice A and B describe structural features that macromolecules can exhibit, whether as single chains or branched forms. Choice D is incorrect as not all macromolecules are used by the body, such as synthetic polymers or certain non-digestible fibers.

2. What enzymes do lysosomes contain, leading to their nickname as the cell's 'suicide bags'?

• A. Hydrolytic enzymes
• B. Ligases (bonding enzymes)
• C. Transferases (molecule transfer)
• D. Oxidoreductases (redox reactions)

Correct answer: A

Rationale: Lysosomes are organelles filled with hydrolytic enzymes that break down proteins, nucleic acids, lipids, and carbohydrates. These enzymes aid in digesting cellular waste and foreign substances, hence the term 'suicide bags' due to their involvement in cell degradation and recycling. Ligases are enzymes that catalyze the joining of two large molecules by forming a new chemical bond, not present in lysosomes. Transferases are enzymes that catalyze the transfer of functional groups from one molecule to another, not found in lysosomes. Oxidoreductases are enzymes involved in oxidation-reduction reactions, which are not the primary function of lysosomes.

3. The small intestine is where most of the chemical digestion and nutrient absorption occur. What is the finger-like projection in the small intestine that increases its surface area for absorption?

• A. Rugae
• B. Villi
• C. Microvilli
• D. All of the above

Correct answer: C

Rationale: Microvilli are the finger-like projections in the small intestine that increase its surface area for absorption. Villi are also present in the small intestine and help increase the surface area for absorption. However, microvilli are smaller structures found on the surface of villi, further increasing the surface area available for nutrient absorption. Rugae are folds in the stomach that allow for expansion when food is consumed and are not found in the small intestine. Therefore, the correct answer is C) Microvilli. Villi and microvilli are specific to the small intestine, playing vital roles in nutrient absorption, while rugae are specific to the stomach's structure and function, serving a different purpose than increasing surface area for absorption.

4. Which hormone regulates the sleep-wake cycle?

• A. Cortisol
• B. Melatonin
• C. Thyroxine
• D. Insulin

Correct answer: B

Rationale: The correct answer is B: Melatonin. Melatonin, produced by the pineal gland, is the hormone that regulates the sleep-wake cycle. It helps signal to the body when it's time to sleep and wake up, playing a crucial role in maintaining a healthy sleep pattern. Choice A, Cortisol, is known as the stress hormone and plays a role in the body's response to stress, not specifically in regulating the sleep-wake cycle. Choice C, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism, not the sleep-wake cycle. Choice D, Insulin, is a hormone produced by the pancreas that regulates blood sugar levels, not the sleep-wake cycle.

5. The endocrine system communicates through chemical messengers called:

• A. Enzymes
• B. Hormones
• C. Antibodies
• D. Neurons

Correct answer: B

Rationale: The correct answer is B: Hormones. The endocrine system communicates through hormones, which are chemical messengers produced by glands and released into the bloodstream to target specific cells or organs in the body. Enzymes are biological molecules that catalyze biochemical reactions, antibodies are part of the immune system, and neurons are cells that transmit nerve impulses. In this context, enzymes, antibodies, and neurons do not play roles in the endocrine system's communication process, making them incorrect choices.

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