Nursing Elites

1. Which of the following organelles is the site of cellular respiration?

• A. Nucleus
• B. Mitochondria
• C. Lysosomes
• D. Ribosomes

Correct answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell because they generate most of the cell's supply of ATP through cellular respiration. The other organelles listed, such as the nucleus (choice A), lysosomes (choice C), and ribosomes (choice D), do not play a direct role in cellular respiration. The nucleus contains genetic material, lysosomes are involved in digestion and waste removal, and ribosomes are responsible for protein synthesis.

2. Which of the following is the term used to represent alternative versions of a gene?

• A. Alleles
• B. Binary fission
• C. Heterozygous
• D. Homozygous

Correct answer: A

Rationale: The correct answer is A: Alleles. Alleles are different versions of a gene that can exist at a specific locus on a chromosome. This term specifically refers to the different forms of a gene that can exist. Choices B, C, and D are incorrect because they do not represent alternative versions of a gene. Binary fission is a form of asexual reproduction in single-celled organisms, while heterozygous and homozygous refer to the genetic makeup of an individual rather than alternative versions of a gene.

3. What function does cholesterol, a phospholipid, serve within the cell membrane?

• A. It builds up fats to make the structure more flexible
• B. It allows protein channels to form
• C. It makes the structure very rigid and impermeable
• D. It stabilizes the membrane structure

Correct answer: D

Rationale: Cholesterol helps to maintain the fluidity and stability of the cell membrane by fitting between the phospholipid molecules. Choice A is incorrect because cholesterol does not build up fats in the cell membrane. Choice B is incorrect as protein channels are formed by proteins, not cholesterol. Choice C is incorrect as cholesterol actually helps regulate the fluidity of the membrane, making it less rigid and more permeable.

4. What percentage of the offspring of the parents is predicted to have a cleft chin?

• A. 25%
• B. 50%
• C. 0%
• D. 75%

Correct answer: A

Rationale: When one parent carries the recessive gene for a cleft chin and the other does not, there is a 25% chance of the offspring inheriting the cleft chin. This is due to the fact that the trait follows a simple Mendelian inheritance pattern, where the offspring would need to inherit the recessive gene from both parents to express the trait. Therefore, 25% of the offspring are predicted to have a cleft chin. Choices B, C, and D are incorrect because the likelihood of inheriting a cleft chin in this specific scenario is 25%, not 50%, 0%, or 75%.

5. At the beginning of meiosis, how many chromosomes does the diploid parent cell have?

• A. 23
• B. 24
• C. 46
• D. 54

Correct answer: C

Rationale: The correct answer is C: 46. At the start of meiosis, the diploid parent cell contains 46 chromosomes. During meiosis, the number of chromosomes is halved, resulting in each gamete having 23 chromosomes. Choice A (23) is incorrect because that is the number of chromosomes in a human gamete, not the parent cell. Choice B (24) and Choice D (54) are also incorrect as they do not reflect the correct number of chromosomes in a diploid parent cell at the beginning of meiosis.

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