Nursing Elites

1. What happens during the S phase of the cell cycle?

• A. Chromosomes are duplicated.
• B. Cell growth occurs.
• C. DNA is synthesized.
• D. DNA is destroyed.

Correct answer: A

Rationale: During the S phase of the cell cycle, chromosomes are duplicated. This is a critical step in cell division as each chromosome is replicated to ensure that the resulting daughter cells receive an identical set of genetic information. Choices B, C, and D are incorrect because cell growth primarily occurs in the G1 phase, DNA synthesis happens during the S phase, and DNA destruction does not occur during any phase of the cell cycle.

2. 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.

3. Which of the following organisms would not have eukaryotic cells?

• A. Bacteria
• B. Dog
• C. Human
• D. Onion

Correct answer: A

Rationale: The correct answer is A, Bacteria. Bacteria do not have eukaryotic cells. They are single-celled organisms with prokaryotic cells. Dogs, humans, and onions are all multicellular organisms that possess eukaryotic cells. Therefore, choices B, C, and D have eukaryotic cells and are not the correct answer.

4. If a hard-boiled egg is placed in a beaker of saltwater, what will happen to the egg?

• A. Expand because water will move into the egg
• B. Shrivel because water will leave the egg
• C. Remain the same
• D. None of the above

Correct answer: B

Rationale: The correct answer is B. When a hard-boiled egg is placed in a beaker of saltwater, the egg will shrivel because water will leave the egg through osmosis. Osmosis is the movement of water from an area of lower solute concentration to an area of higher solute concentration, in this case, from the egg into the saltwater. The higher concentration of solute in the saltwater causes water to move out of the egg, leading to the egg shrinking or shriveling. Choices A, C, and D are incorrect because the egg will not expand, remain the same, or have an outcome different from shriveling when placed in a beaker of saltwater.

5. Physical factors such as temperature and pH can alter enzyme activity because they have an effect on the enzyme's ___________.

• A. acidity
• B. shape
• C. chemistry
• D. substrate

Correct answer: B

Rationale: Physical factors such as temperature and pH can alter enzyme activity by affecting the enzyme's shape. Enzymes rely on their specific shapes to function properly and catalyze reactions. Any changes in temperature or pH can disrupt these shapes, causing the enzyme to become denatured and lose its functionality. Therefore, alterations in temperature and pH can impact enzyme activity by directly affecting their shapes. Choices A, C, and D are incorrect because while pH can affect acidity and chemical properties of the enzyme, and temperature can influence the enzyme-substrate interaction, the primary reason for enzyme activity alteration due to temperature and pH is the change in the enzyme's shape.

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