Nursing Elites

1. How do green plants use nitrates in the nitrogen cycle?

• A. To synthesize proteins
• B. To store food
• C. To decompose ammonia
• D. To break down nitrites

Correct answer: A

Rationale: Green plants use nitrates in the nitrogen cycle to synthesize proteins. Nitrogen is an essential component of amino acids, which are the building blocks of proteins. Plants take up nitrates from the soil through their roots and incorporate nitrogen into their proteins through the process of protein biosynthesis. This helps in their growth, development, and overall health. Choice B, 'To store food,' is incorrect because nitrates are primarily used for protein synthesis, not food storage. Choice C, 'To decompose ammonia,' is incorrect as plants do not decompose ammonia but rather utilize it through nitrification. Choice D, 'To break down nitrites,' is incorrect as plants typically convert nitrites into nitrates through a process called nitrate assimilation for protein synthesis.

2. Three students measured the mass of a product of combustion. They recorded measurements of 14 g, 16 g, and 17 g. If the known mass of the product is 30 g, how would you describe the students’ measurements?

• A. Accurate
• B. Precise
• C. Both accurate and precise
• D. Neither accurate nor precise

Correct answer: B

Rationale: The students' measurements are precise because they are consistently close to each other. However, they are not accurate because all the measurements deviate from the known mass of the product (30 g). Accuracy refers to how close a measurement is to the true or accepted value, while precision refers to the level of agreement among repeated measurements. Since the students' measurements are consistent but do not align with the true value, they can be considered precise but not accurate. Choice A is incorrect because accuracy relates to the proximity of the measurements to the true value, which is not the case here. Choice C is incorrect because although the measurements are precise, they are not accurate. Choice D is incorrect because the measurements are precise as they show good agreement with each other, even though they are not accurate.

3. Why do high-salt content foods not require refrigeration to prevent spoilage?

• A. Osmosis
• B. Diffusion
• C. Active transport
• D. Passive transport

Correct answer: A

Rationale: Osmosis is the natural process that prevents high-salt content foods from spoiling without the need for refrigeration. Osmosis involves the movement of water across a semi-permeable membrane from an area of lower solute concentration (water) to an area of higher solute concentration (salt). In high-salt content foods, the salt acts as a preservative by drawing moisture out of bacteria or other microorganisms, making it difficult for them to survive and spoil the food. This process helps in preserving the food and preventing spoilage even without refrigeration. Choices B, C, and D are incorrect because they do not involve the specific mechanism of water movement in response to the salt concentration in high-salt content foods.

4. Phenotype refers to the _ of an individual.

• A. Genetic makeup
• B. Actual physical appearance
• C. Recessive alleles
• D. None of the above

Correct answer: B

Rationale: Phenotype refers to the actual physical appearance and characteristics of an individual, which are determined by the interaction of both genetic makeup (genotype) and environmental factors. It includes visible traits such as height, eye color, and hair type. Choice A, genetic makeup, refers to the genotype, which is the genetic constitution of an organism. Choice C, recessive alleles, is a specific type of gene variant and does not encompass the entire concept of phenotype. Choice D, none of the above, is incorrect as phenotype does refer to the actual physical appearance of an individual.

5. What happens during anaphase?

• A. Chromosomes move to opposite ends of the spindle.
• B. Nuclear membrane and nucleoli disintegrate.
• C. Chromatids line up at the center of the spindle.
• D. Nuclear membrane and nucleoli form.

Correct answer: A

Rationale: During anaphase, the sister chromatids, joined at the centromere, separate and move towards opposite ends of the spindle apparatus. This movement ensures that each daughter cell receives an identical set of chromosomes. Choice B is incorrect as the disintegration of the nuclear membrane and nucleoli occurs during prophase. Choice C is incorrect as chromatids align at the center of the spindle during metaphase, not anaphase. Choice D is incorrect as the formation of the nuclear membrane and nucleoli occurs during telophase, not anaphase.

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