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 organelle is the site of photosynthesis in plant cells?

• A. Mitochondria
• B. Chloroplasts
• C. Ribosomes
• D. Endoplasmic Reticulum

Correct answer: B

Rationale: The correct answer is B: Chloroplasts. Chloroplasts are responsible for conducting photosynthesis in plant cells. They contain chlorophyll, a pigment that captures light energy and converts it into chemical energy through the process of photosynthesis. Mitochondria (choice A) are known as the powerhouse of the cell and are involved in cellular respiration, not photosynthesis. Ribosomes (choice C) are responsible for protein synthesis. The endoplasmic reticulum (choice D) is involved in protein and lipid synthesis and transport within the cell, not photosynthesis.

3. Which of the following is not true about enzymes?

• A. They catalyze reactions
• B. They lower the activation energy needed
• C. They have an active site
• D. They are typically proteins

Correct answer: B

Rationale: Enzymes lower the activation energy needed for a reaction to occur, not raise it. By lowering the activation energy, enzymes facilitate reactions, making them occur more easily and rapidly. Choice A is correct as enzymes indeed catalyze reactions. Choice C is correct as enzymes have specific active sites where substrates bind. Choice D is correct as enzymes are commonly proteins, although some RNA molecules also exhibit catalytic properties.

4. What is the term for the movement of ions and other molecular substances across cell membranes without the need for energy?

• A. Active Transport
• B. Passive Transport
• C. Diffusion
• D. Osmosis

Correct answer: B

Rationale: Passive transport refers to the movement of substances across cell membranes without the need for energy input. In contrast, active transport, choice A, requires energy to move substances against their concentration gradient. Diffusion, choice C, is a type of passive transport where substances move from an area of high concentration to low concentration. Osmosis, choice D, specifically refers to the movement of water molecules across a selectively permeable membrane.

5. What are the three types of muscle tissue?

• A. Cardiac, spinal, stomach
• B. Smooth, skeletal, cardiac
• C. Neuron, epithelial, collagen
• D. None of the above

Correct answer: B

Rationale: The correct answer is B: Smooth, skeletal, cardiac. Smooth muscle is found in organs like the stomach and is involuntarily controlled. Skeletal muscle is found in voluntary muscles, like the bicep or quadriceps. Cardiac muscle is found only in the heart walls and works involuntarily to make the heart beat and pump blood. Choices A, C, and D are incorrect because they do not represent the three types of muscle tissue.

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