Nursing Elites

1. What is the 'lock-and-key' model?

• A. Protein folding
• B. Enzyme-substrate interaction
• C. Muscle contraction
• D. Blood clotting

Correct answer: B

Rationale: The 'lock-and-key' model describes the specificity of the interaction between enzymes and their substrates. In this model, the enzyme's active site acts like a lock that can only be opened by the specific substrate molecule, which serves as the key. This specific binding ensures that enzymes catalyze particular reactions and do not interact with other molecules indiscriminately. Protein folding (option A) is the process by which a protein attains its functional three-dimensional structure but is not directly related to the lock-and-key model. Muscle contraction (option C) and blood clotting (option D) are complex biological processes but are not directly associated with the lock-and-key model of enzyme-substrate interaction.

2. Which hormone, produced by the pancreas, regulates blood sugar levels by promoting the uptake of glucose into cells?

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

Correct answer: A

Rationale: Insulin is the correct answer. It is produced by the pancreas and plays a crucial role in regulating blood sugar levels by facilitating the absorption of glucose into cells. When blood sugar levels are elevated, insulin is released to help cells utilize glucose for energy or store it for future use. Glucagon, choice B, is produced by the pancreas as well but has the opposite effect of raising blood sugar levels by releasing stored glucose into the bloodstream. Cortisol, choice C, is a hormone produced by the adrenal glands that is involved in the stress response and metabolism, not specifically in regulating blood sugar levels. Thyroxine, choice D, is a hormone produced by the thyroid gland that regulates metabolism but is not directly involved in the uptake of glucose into cells.

3. Which term refers to a position farther from the midline of the body? For example, the little toe is lateral to the big toe on the same foot.

• A. Lateral
• B. Medial
• C. Proximal
• D. Distal

Correct answer: A

Rationale: The correct answer is A: Lateral. Lateral refers to a position farther away from the midline of the body. In the example provided, the little toe is indeed lateral to the big toe on the same foot. This is in contrast to 'medial,' which means closer to the midline. 'Proximal' refers to a position closer to the point of attachment or the trunk of the body, while 'distal' refers to a position farther from the point of attachment or the trunk of the body.

4. What type of intermolecular force is responsible for the high surface tension of water?

• A. Hydrogen bonding
• B. London dispersion forces
• C. Ionic bonding
• D. Metallic bonding

Correct answer: A

Rationale: The high surface tension of water is primarily due to the strong hydrogen bonding between water molecules. Hydrogen bonding is a specific type of intermolecular force that occurs between a hydrogen atom covalently bonded to a highly electronegative atom, like oxygen in water, and another electronegative atom nearby. This unique interaction results in a strong attraction between water molecules at the surface, leading to the cohesive forces responsible for the high surface tension of water. Choices B, C, and D are incorrect because London dispersion forces, ionic bonding, and metallic bonding do not account for the high surface tension observed in water. London dispersion forces are relatively weaker intermolecular forces, while ionic and metallic bonding are types of intramolecular forces that do not directly contribute to the surface tension of water.

5. Which of the following statements regarding macrophages is incorrect?

• A. They are found abundantly in the blood
• B. They are larger than neutrophils
• C. They are long-lived
• D. They are made in the bone marrow as monocytes, called macrophages once they reach organs

Correct answer: A

Rationale: The correct answer is A. Macrophages are not found abundantly in the blood; they are present in tissues and organs. Macrophages are tissue-resident immune cells that play a key role in immune responses and are derived from monocytes produced in the bone marrow. Choice B is correct as macrophages are larger than neutrophils. Choice C is correct as macrophages are long-lived cells. Choice D is correct as macrophages originate in the bone marrow as monocytes and differentiate into macrophages once they migrate to various tissues and organs.

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