Nursing Elites

1. Which of the following is not one of the four nitrogenous bases that make up the DNA structure?

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

Correct answer: C

Rationale: The correct answer is C: Uracil. Uracil is found in RNA, not DNA. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine. Choice A, Adenine, is a nitrogenous base in DNA. Choice B, Guanine, is another nitrogenous base in DNA. Choice D, Thymine, is also one of the four nitrogenous bases in DNA. Therefore, the correct answer is Uracil (Choice C).

2. Phagocytes in the immune system are responsible for the biological action of which of the following?

• A. Secreting
• B. Consuming
• C. Altering
• D. Building

Correct answer: B

Rationale: The correct answer is B: Consuming. Phagocytes are cells that engulf and digest pathogens, dead cells, and other harmful particles, playing a crucial role in the immune system's defense. Phagocytes do not secrete substances, alter particles, or build structures; their primary function is to consume and eliminate harmful entities.

3. In the hierarchy of biology, cells combine to form which of the following?

• A. Macromolecules
• B. Molecules
• C. Tissues
• D. Organelles

Correct answer: C

Rationale: In the hierarchy of biology, cells combine to form tissues. Tissues are groups of cells that work together to perform specific functions. This is a fundamental level of organization above individual cells but below organs and organ systems. Macromolecules and molecules are smaller components that make up cells, not what cells combine to form. Organelles are structures within cells that perform specific functions and do not result from the combination of cells.

4. During which stage of photosynthesis is solar energy converted to chemical energy?

• A. During phosphate synthesis
• B. During light reactions
• C. During the Krebs cycle
• D. During the Calvin cycle

Correct answer: B

Rationale: The correct answer is B, during the light reactions. During the light reactions of photosynthesis, solar energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH. Choice A is incorrect as phosphate synthesis does not involve the conversion of solar energy. Choice C, the Krebs cycle, is a part of cellular respiration, not photosynthesis. Choice D, the Calvin cycle, is responsible for fixing carbon dioxide into carbohydrates and does not involve the direct conversion of solar energy to chemical energy.

5. What is the difference between saturated and unsaturated fatty acids?

• A. There is no difference between saturated and unsaturated fatty acids.
• B. Saturated fatty acids contain double bonds, unlike unsaturated fatty acids.
• C. Saturated fatty acids often contain two or more pairs of double bonds, unlike unsaturated fatty acids.
• D. Saturated fatty acids contain no double bonds, unlike unsaturated fatty acids.

Correct answer: D

Rationale: The correct answer is D. Saturated fatty acids contain no double bonds between the carbon atoms in their hydrocarbon chains, making them more solid at room temperature. Choice A is incorrect because there is a significant difference between saturated and unsaturated fatty acids. Choice B is incorrect as it inaccurately states that saturated fatty acids contain double bonds, which is a property of unsaturated fatty acids. Choice C is also incorrect as saturated fatty acids do not contain double bonds, let alone two or more pairs of double bonds.

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