Nursing Elites

1. The dark, round structures observed within some bacterial cells are most likely:

• A. Ribosomes
• B. Flagella
• C. Endospores
• D. Capsules

Correct answer: C

Rationale: Endospores are the correct answer. Endospores are dark, round structures observed within some bacterial cells. They are highly resistant dormant structures formed by certain bacteria in response to harsh environmental conditions. Ribosomes are not dark, round structures within bacterial cells; they are responsible for protein synthesis. Flagella are long, whip-like appendages used for movement and are not dark, round structures within bacterial cells. Capsules are outer layers of polysaccharides that some bacteria produce for protection and adherence, not dark, round structures within bacterial cells.

2. Why is warming up before exercise important?

• A. To prevent dehydration
• B. To prevent muscle soreness
• C. To prevent increased heart rate
• D. To prevent low blood sugar

Correct answer: B

Rationale: Warming up before exercise is crucial to prevent muscle soreness. It helps by increasing blood flow to the muscles, improving flexibility, and preparing the body for physical activity. Dehydration, increased heart rate, and low blood sugar are not directly prevented by warming up before exercise. Dehydration is prevented by proper hydration before and during exercise; increased heart rate is a normal physiological response to exercise; and low blood sugar is managed through proper nutrition and timing of meals before physical activity.

3. What two factors enable some intercellular chemical signals to diffuse across cell membranes and bind to intracellular receptors?

• A. They are small and soluble.
• B. They are large and soluble.
• C. They are small and insoluble.
• D. They are large and insoluble.

Correct answer: A

Rationale: The correct answer is A: 'They are small and soluble.' Small and soluble molecules can easily pass through cell membranes and bind to intracellular receptors. Being small allows them to pass through the membrane, while being soluble enables them to dissolve in the aqueous environment inside the cell. Choice B is incorrect because large molecules typically cannot pass through the cell membrane easily. Choices C and D are incorrect because insoluble molecules would not dissolve in the aqueous environment inside the cell, hindering their ability to bind to intracellular receptors.

4. Which of the following structures is found in the nucleus of a cell?

• A. Mitochondria
• B. Endoplasmic reticulum
• C. Chromosomes
• D. Ribosomes

Correct answer: C

Rationale: Chromosomes, which contain genetic information, are found in the nucleus of a cell. They play a crucial role in cell division, gene expression, and inheritance. Mitochondria, responsible for energy production, are located in the cytoplasm, not the nucleus. The endoplasmic reticulum is mainly involved in protein and lipid synthesis and is not a component of the nucleus. Ribosomes, essential for protein synthesis, are found in the cytoplasm and on the endoplasmic reticulum, but not in the nucleus.

5. What phenomenon explains the bending of light as it passes around an obstacle or through an aperture?

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Dispersion

Correct answer: C

Rationale: Diffraction is the phenomenon that explains the bending of light as it passes around an obstacle or through an aperture. When light encounters an obstacle or passes through an aperture, it diffracts, causing it to bend around the edges. Refraction, on the other hand, occurs when light passes from one medium to another, causing it to change direction. Reflection involves the bouncing back of light rays from a surface, and dispersion is the separation of light into its different colors. Therefore, the correct answer is C, as diffraction specifically addresses the bending of light as it interacts with obstacles or apertures, unlike the other choices that describe different optical phenomena.

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