Nursing Elites

1. How do vaccines stimulate the immune system to develop memory without causing full-blown illness? What type of molecule in a vaccine typically triggers the immune response?

• A. Toxins produced by the pathogen
• B. Live, attenuated (weakened) forms of the pathogen
• C. Inactivated (dead) forms of the pathogen
• D. Antigens (specific molecules) from the pathogen

Correct answer: D

Rationale: Vaccines work by triggering the immune system to develop memory without causing illness. They typically contain antigens, which are specific molecules from the pathogen. These antigens stimulate the immune system to produce a targeted immune response without causing full-blown sickness. By presenting these antigens, vaccines help the immune system create memory cells that remember the pathogen. This memory allows the immune system to respond more effectively if it encounters the pathogen in the future. Choices A, B, and C are incorrect because vaccines do not typically contain toxins, live pathogens, or inactivated forms of the pathogen. Instead, vaccines primarily rely on specific molecules (antigens) to induce an immune response.

2. What is the general formula for an alkyl halide?

• A. CₙH₂ₙ
• B. CₙH₂ₙ₊₂
• C. CₙH₂ₙ₊₁X
• D. CₙH₂ₙO

Correct answer: C

Rationale: The correct answer is option C, 'CₙH₂ₙ₊₁X.' This is the general formula for an alkyl halide, where X represents a halogen atom (such as fluorine, chlorine, bromine, or iodine), and the hydrocarbon chain is represented by CₙH₂ₙ₊₁. Option A, 'CₙH₂ₙ,' is incorrect because it does not account for the presence of a halogen atom. Option B, 'CₙH₂ₙ₊₂,' is incorrect as it represents an alkene, not an alkyl halide. Option D, 'CₙH₂ₙO,' is also incorrect as it suggests the presence of oxygen, which is not characteristic of alkyl halides.

3. What is the name for the smallest amount of an element that can exist independently and retain its chemical properties?

• A. Atom
• B. Molecule
• C. Compound
• D. Mixture

Correct answer: A

Rationale: The correct answer is 'Atom.' An atom is the fundamental unit of an element that can exist independently and retain its unique chemical properties. It consists of a nucleus containing protons and neutrons, surrounded by electrons. Choice B, 'Molecule,' is incorrect because a molecule is a combination of two or more atoms bonded together. Choice C, 'Compound,' is incorrect as a compound is a substance formed by the chemical combination of two or more different elements. Choice D, 'Mixture,' is incorrect since a mixture is a blend of two or more substances physically combined, but the individual components retain their properties.

4. Which blood component is responsible for the production of antibodies?

• A. Platelets
• B. Red blood cells
• C. White blood cells
• D. Plasma cells

Correct answer: C

Rationale: White blood cells, specifically B lymphocytes or B cells, are responsible for producing antibodies as part of the immune response. When the body encounters foreign substances (antigens), B cells are activated to differentiate into plasma cells, which then produce antibodies to target and neutralize the antigens. Platelets are involved in blood clotting and not in antibody production. Red blood cells are primarily responsible for carrying oxygen in the blood and do not produce antibodies. Plasma cells are actually differentiated B cells that produce antibodies, but the question asks for the blood component responsible for the production of antibodies, which is the white blood cells.

5. What is the primary cause of acne vulgaris, commonly known as acne?

• A. Dry skin
• B. Clogged pores and excess oil production
• C. Bacterial infection alone
• D. Vitamin deficiency

Correct answer: B

Rationale: The primary cause of acne vulgaris is clogged pores and excess oil production. Acne develops when hair follicles become clogged with oil and dead skin cells, creating an environment for bacteria to thrive, leading to inflammation and acne breakouts. While dry skin, bacterial infection alone, and vitamin deficiency can contribute to acne, they are not the main underlying cause. Therefore, the correct answer is clogged pores and excess oil production, as they form the basis for the development of acne vulgaris.

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