Nursing Elites

1. Choose the correct pronoun to complete the sentence: "Neither Michael nor Sarah ____ their homework finished yet."

• A. has
• B. have
• C. are having
• D. does have

Correct answer: B

Rationale: When referring to "neither" followed by two subjects, the verb agrees with the plural subject ("Sarah"). So, "have" is the correct answer.

2. Which phenomenon explains the formation of rainbows in the sky?

• A. Diffraction
• B. Interference
• C. Refraction and dispersion of sunlight by water droplets.
• D. Reflection from clouds

Correct answer: C

Rationale: Refraction and dispersion of sunlight by water droplets in the atmosphere separate white light into its constituent colors, creating the rainbow phenomenon.

3. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear

• A. Pink
• B. Blue
• C. Red
• D. Purple

Correct answer: D

Rationale: Rationale: The Gram stain is a differential staining technique that divides bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. As a result, Gram-positive bacteria appear purple under the microscope after staining. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, causing them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain.

4. In plant cells, what structure provides rigidity and support?

• A. Cell membrane
• B. Golgi apparatus
• C. Plastid
• D. Cell wall

Correct answer: D

Rationale: The correct answer is D: Cell wall. The cell wall is a rigid structure found in plant cells that provides support and protection. It is composed of cellulose and other materials, forming a tough outer layer that helps maintain the cell's shape and prevents it from bursting under pressure. The cell membrane (option A) is a semi-permeable barrier that surrounds the cell but does not provide rigidity. The Golgi apparatus (option B) is involved in sorting and packaging proteins. Plastids (option C) are organelles responsible for functions like photosynthesis and storage, but they do not provide rigidity and support like the cell wall does.

5. A scientist observes a new chemical reaction and proposes a mechanism for how it occurs. What is the BEST way to test this mechanism?

• A. Simulate the reaction using computer models.
• B. Design experiments to manipulate predicted intermediate steps.
• C. Compare the reaction to similar known reactions.
• D. Publish the mechanism in a scientific journal.

Correct answer: B

Rationale: Designing experiments to manipulate predicted intermediate steps is the best way to test the proposed mechanism because it directly tests the validity of the proposed mechanism by manipulating the specific steps involved. This approach allows for empirical validation of the proposed mechanism and provides concrete evidence to support or refute it. Simulating the reaction using computer models may provide some insights but does not directly test the mechanism. Comparing the reaction to similar known reactions can provide some context but does not directly test the proposed mechanism. Publishing the mechanism in a scientific journal is important for sharing findings but does not constitute a test of the mechanism itself.

6. Acne vulgaris, commonly known as acne, is primarily caused by

• A. Dry skin (Dry skin can worsen acne but isn't the primary cause)
• B. Clogged pores and excess oil production
• C. Bacterial infection alone (Bacteria play a role but not the sole cause)
• D. Vitamin deficiency

Correct answer: B

Rationale: The correct answer is B: 'Clogged pores and excess oil production.' Acne vulgaris, or acne, is primarily caused by a combination of factors including excess sebum (oil) production by the skin's sebaceous glands and the accumulation of dead skin cells, leading to clogged pores. This environment provides a breeding ground for acne-causing bacteria, contributing to inflammation and the formation of pimples. While factors like dry skin, bacterial infections, and even vitamin deficiencies can exacerbate acne, they are not the primary cause. Thus, B is the most accurate option for the primary cause of acne.

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