Nursing Elites

1. Which organelle is responsible for making proteins?

• A. Ribosome
• B. Chloroplast
• C. Lysosome
• D. Mitochondrion

Correct answer: A

Rationale: Ribosomes are the organelles responsible for protein synthesis within the cell. They are the sites where amino acids are linked together to form proteins based on the instructions carried by mRNA (messenger RNA). Ribosomes can be found free-floating in the cytoplasm or attached to the endoplasmic reticulum, and they play a crucial role in translating genetic information into proteins. Chloroplasts are responsible for photosynthesis, lysosomes are involved in digestion and waste removal, and mitochondria are known as the powerhouse of the cell responsible for energy production through cellular respiration. Therefore, the ribosome is the correct organelle responsible for making proteins.

2. Which two bases are purines?

• A. Adenine (A)
• B. Cytosine (C)
• C. Thymine (T)
• D. Guanine (G)

Correct answer: A

Rationale: Adenine (A) and guanine (G) are the two bases that are purines. Purines are characterized by a double-ring structure containing two carbon rings, distinguishing them from pyrimidines. Adenine and guanine are purines because they possess this unique double-ring structure. Therefore, choices A and D, adenine and guanine, respectively, are the correct answers. Choices B and C, cytosine and thymine, are pyrimidines and do not exhibit the double-ring structure characteristic of purines.

3. How are lipids different from other organic molecules?

• A. They are indivisible.
• B. They are not water soluble.
• C. They contain zinc.
• D. They form long proteins.

Correct answer: B

Rationale: The correct answer is B: 'They are not water soluble.' Lipids are not water-soluble, which distinguishes them from other organic molecules. Choice A is incorrect because lipids are not indivisible; they can be broken down into fatty acids and glycerol. Choice C is incorrect as lipids do not necessarily contain zinc; they are a diverse group of molecules. Choice D is incorrect because lipids do not form long proteins; proteins are made up of amino acids, not lipids.

4. Which, if any, of the following statements are true?

• A. Water boils at approximately 100°C (212°F) at standard atmospheric pressure
• B. The boiling point is the temperature at which the vapor pressure is higher than the atmospheric pressure around the water
• C. Water boils at a lower temperature in areas of lower pressure
• D. A and C are true

Correct answer: D

Rationale: Both statements A and C are true. Water indeed boils at approximately 100°C (212°F) at standard atmospheric pressure. However, water boils at a lower temperature in areas of lower pressure due to the decreased atmospheric pressure, which affects the vapor pressure and boiling point of water. Statement B is incorrect because the boiling point is the temperature at which the vapor pressure equals the external pressure (atmospheric pressure in this case), not when it is higher.

5. Why do gardeners sometimes use salt to get rid of slugs?

• A. The salt moves from the exterior into the slug’s body.
• B. The salt causes water in the slug to move outward.
• C. The salt and slug slime merge to form a new compound.
• D. The salt’s corrosiveness breaks down the slug’s cell walls.

Correct answer: D

Rationale: Gardeners use salt to get rid of slugs because salt is corrosive and breaks down the slug's cell walls. When the slug comes into contact with salt, the salt draws moisture out of the slug's body, causing dehydration and ultimately leading to the slug's death. Choices A, B, and C are incorrect because the primary mechanism of salt in eliminating slugs is its corrosive action on the slug's body, not the movement of salt into the slug's body, outward movement of water in the slug, or merging with slug slime to form a new compound.

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