Nursing Elites

1. During which phase is the chromosome number reduced from diploid to haploid?

• A. S phase
• B. interphase
• C. mitosis
• D. meiosis I

Correct answer: D

Rationale: The correct answer is 'meiosis I.' During meiosis I, the chromosome number is reduced from diploid to haploid through two rounds of division. Choice A ('S phase') is incorrect as the S phase is part of the cell cycle where DNA is replicated. Choice B ('interphase') is also incorrect as interphase is the phase where the cell prepares for division. Choice C ('mitosis') is incorrect as mitosis is a process where a diploid cell divides to produce two identical diploid daughter cells, maintaining the chromosome number.

2. Why is DNA important for metabolic activities of the cell?

• A. It controls the synthesis of enzymes.
• B. It stabilizes the cell wall.
• C. It initiates cell division.
• D. It prevents diffusion of nutrients.

Correct answer: A

Rationale: The correct answer is A. DNA plays a crucial role in metabolic activities by controlling the synthesis of enzymes. Enzymes are the biological catalysts that regulate and facilitate metabolic reactions within the cell. Choice B is incorrect because DNA is not involved in stabilizing the cell wall; that role is usually associated with other components like the cell membrane. Choice C is incorrect as cell division is primarily regulated by different processes and molecules, not directly by DNA. Choice D is incorrect because DNA is not related to preventing the diffusion of nutrients; instead, it is involved in coding for proteins that aid in various cellular functions.

3. How many chromosomes do sperm and egg produce in meiosis?

• A. 46
• B. 23
• C. 45
• D. 24

Correct answer: B

Rationale: Sperm and egg cells undergo meiosis to form gametes with half the number of chromosomes found in somatic cells. Each sperm and egg cell produces 23 chromosomes through meiosis. Choice A is incorrect because 46 chromosomes represent the diploid number found in somatic cells. Choice C is incorrect as it is an uncommon number for chromosome production in human gametes. Choice D is incorrect as the total number of chromosomes in sperm or egg cells is 23, not 24.

4. A cell is in a solution in which the concentration of solutes is higher inside the cell than outside the cell. What would you expect to happen to the cell?

• A. It will swell and possibly burst.
• B. It will shrivel and shrink.
• C. It will maintain its current size.
• D. It will grow a supportive cell wall.

Correct answer: A

Rationale: When a cell is in a solution where the concentration of solutes is higher inside the cell than outside, it is in a hypertonic environment. In this situation, water will move into the cell in an attempt to equalize the concentration of solutes on both sides of the cell membrane through the process of osmosis. As a result, the cell will swell as it takes in more water, potentially leading to bursting or cell lysis. Choice B is incorrect because a cell in a hypertonic solution will not shrivel and shrink due to water moving into the cell. Choice C is incorrect because the cell will not maintain its current size; it will swell. Choice D is incorrect because growing a supportive cell wall is not the immediate response to being in a hypertonic environment.

5. Which statement is true of enzymes?

• A. They are made from lipids.
• B. They are made from proteins.
• C. They form double chains of DNA.
• D. They bind with catalysts.

Correct answer: B

Rationale: The correct answer is B: Enzymes are made from proteins. Enzymes are biological molecules that act as catalysts to speed up chemical reactions in living organisms. While the majority of enzymes are proteins, a few are made from RNA. The statement that enzymes are made from lipids (choice A) is incorrect. Enzymes do not form double chains of DNA (choice C) as their primary function is not related to DNA structure. Additionally, enzymes themselves do not bind with catalysts (choice D); instead, they act as catalysts to facilitate reactions.

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