Nursing Elites

1. Which of the following bases is not present in RNA?

• A. Adenine
• B. Thymine
• C. Uracil
• D. Cytosine

Correct answer: B

Rationale: Thymine is not present in RNA. RNA uses uracil as one of its bases, which pairs with adenine. In RNA, adenine does not pair with thymine as in DNA. Cytosine and guanine are the other two bases found in both RNA and DNA.

2. Which of the following organelles is responsible for producing ATP in cells?

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

Correct answer: B

Rationale: The correct answer is 'Mitochondrion.' Mitochondria are known as the powerhouse of the cell and are responsible for producing ATP, the energy currency of the cell. The nucleus is responsible for storing genetic material and controlling cell activities, not for ATP production. Chloroplasts are found in plant cells and are responsible for photosynthesis, not ATP production. Lysosomes are involved in digestion and waste removal, not ATP production.

3. Which statement regarding energy content is true?

• A. Decomposers < secondary consumers
• B. Primary consumers < producers
• C. Producers > secondary consumers
• D. Secondary consumers < primary consumers

Correct answer: C

Rationale: The correct answer is C: "Producers > secondary consumers." Producers, like plants, are the foundation of the energy pyramid, containing the highest energy content in an ecosystem. They convert solar energy into chemical energy through photosynthesis. Secondary consumers, being organisms that feed on other organisms, have lower energy content compared to producers. This hierarchy in energy content is due to the transfer of energy through trophic levels. Choice A is incorrect because decomposers, though essential for nutrient recycling, typically have lower energy content than secondary consumers. Choice B is incorrect because primary consumers, which feed directly on producers, have lower energy content than producers. Choice D is incorrect because secondary consumers have lower energy content compared to primary consumers.

4. The phases of mitosis include:

• A. Prophase, interphase, metaphase, anaphase, and telophase
• B. Prophase, prophase, metaphase, anaphase, and cytokinesis
• C. Prophase, prometaphase, metaphase, anaphase, and telophase
• D. Prophase, interphase, prophase, anaphase, and telophase

Correct answer: C

Rationale: The correct phases of mitosis are prophase, prometaphase, metaphase, anaphase, and telophase. Prophase is the first phase where chromatin condenses into chromosomes, the nuclear envelope breaks down, and the mitotic spindle forms. Prometaphase follows prophase, involving the full disintegration of the nuclear envelope and the attachment of spindle fibers to the kinetochores of the chromosomes. Metaphase is where chromosomes align along the metaphase plate. Anaphase is the phase where sister chromatids separate and move towards opposite poles. Telophase marks the final stage of mitosis, involving the decondensation of chromosomes and the reformation of the nuclear envelope. Choice A is incorrect because it includes interphase, which is not a phase of mitosis. Choice B is incorrect as it repeats prophase, which is the initial phase. Choice D is incorrect because it includes interphase and repeats prophase.

5. How many different types of nucleotides are there in DNA?

• A. one
• B. two
• C. four
• D. eight

Correct answer: C

Rationale: The correct answer is 'C: four.' DNA is composed of four different types of nucleotides: adenine, thymine, guanine, and cytosine. These nucleotides pair up in specific combinations to form the genetic code. Choices 'A: one,' 'B: two,' and 'D: eight' are incorrect because DNA consists of a set of four distinct nucleotides, not one, two, or eight.

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