Nursing Elites

1. Which of the following is the carbohydrate monomer?

• A. Disaccharide
• B. Lactose
• C. Monosaccharide
• D. Thymine

Correct answer: C

Rationale: The correct answer is C: Monosaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit. They are considered the carbohydrate monomers from which larger carbohydrates like disaccharides (composed of two sugar units) and polysaccharides (containing multiple sugar units) are built. Choices A and B, Disaccharide and Lactose, are not monomers but rather specific types of carbohydrates made up of multiple sugar units. Choice D, Thymine, is a nitrogenous base present in DNA and RNA, not a carbohydrate monomer.

2. When water boils, it changes from a liquid to a gas. This is an example of a:

• A. Chemical reaction
• B. Physical change
• C. Nuclear reaction
• D. Biological process

Correct answer: B

Rationale: This is a physical change because boiling water involves a change in state from liquid to gas without altering the chemical composition of the water molecules. In a chemical reaction, new substances are formed by breaking and forming chemical bonds, which is not the case during boiling. A nuclear reaction involves changes in atomic nuclei, which are not occurring during boiling. A biological process refers to activities related to living organisms, which is not applicable to the change from liquid to gas in boiling water.

3. 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.

4. What is the term for the transfer of energy through a food chain?

• A. Photosynthesis
• B. Cellular respiration
• C. Transpiration
• D. Trophic cascade

Correct answer: D

Rationale: Rationale: A) Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll. B) Cellular respiration is the process by which cells break down glucose and other molecules to produce energy in the form of ATP. C) Transpiration is the process by which water is absorbed by plant roots, moves through the plant, and is released as vapor through pores in the leaves. D) Trophic cascade refers to the transfer of energy through a food chain or food web, where the impact of a predator on its prey cascades down the food chain, affecting multiple trophic levels. This term describes the indirect effects that predators can have on lower trophic levels, influencing the entire ecosystem.

5. Which of the following produces the first heart sound ('lub')?

• A. The closing of the aortic and pulmonary valves
• B. The closing of the tricuspid and mitral valves
• C. The opening of the aortic and pulmonary valves
• D. The opening of the tricuspid and mitral valves

Correct answer: B

Rationale: The correct answer is B. The first heart sound, known as the 'lub' sound, is produced by the closure of the tricuspid and mitral valves, which are the atrioventricular valves. This sound marks the beginning of systole in the cardiac cycle. Choice A, the closing of the aortic and pulmonary valves, is incorrect as these valves produce the second heart sound ('dub'). Choice C, the opening of the aortic and pulmonary valves, is incorrect because the first heart sound occurs during ventricular contraction (systole). Choice D, the opening of the tricuspid and mitral valves, is incorrect as the 'lub' sound is associated with the closure, not the opening, of these valves.

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