Nursing Elites

1. Which term refers to a molecule of DNA and structural protein?

• A. Lysosome
• B. Centrosome
• C. Chromosome
• D. Genome

Correct answer: C

Rationale: The correct answer is C: Chromosome. A chromosome is a structure composed of DNA and proteins that carries genetic information. It is the condensed form of DNA associated with structural proteins, not just a molecule of DNA or protein. Lysosomes are membrane-bound organelles containing digestive enzymes, not DNA and protein. Centrosomes are involved in cell division, not related to DNA and protein together. A genome refers to an organism's complete set of DNA, not specifically a molecule containing both DNA and structural protein.

2. What do lacteals absorb in the small intestine?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Nonpolar nutrients

Correct answer: B

Rationale: Lacteals are lymphatic capillaries in the small intestine that specialize in absorbing dietary lipids. These lipids are then transported into the lymphatic system for further processing and distribution throughout the body. Choice A (Carbohydrates) is incorrect because carbohydrates are primarily digested and absorbed in the small intestine by enzymes and transported to the liver. Choice C (Proteins) is incorrect because proteins are broken down into amino acids and absorbed in the small intestine, mainly by the villi. Choice D (Nonpolar nutrients) is incorrect as it is a vague term and not specific to what lacteals absorb, which are primarily lipids.

3. The Hardy-Weinberg equilibrium describes a population that is:

• A. Undergoing rapid evolution due to strong directional selection.
• B. Not evolving and at genetic equilibrium with stable allele frequencies.
• C. Experiencing a founder effect leading to a reduction in genetic diversity.
• D. Dominated by a single homozygous genotype that eliminates all variation.

Correct answer: B

Rationale: The Hardy-Weinberg equilibrium describes a theoretical population in which allele frequencies remain constant from generation to generation, indicating that the population is not evolving. This equilibrium occurs under specific conditions: no mutation, no gene flow, random mating, a large population size, and no natural selection. In this scenario, all genotypes are in proportion to the allele frequencies, and genetic diversity is maintained. Options A, C, and D do not accurately describe a population in Hardy-Weinberg equilibrium. Option A suggests rapid evolution due to strong directional selection, which would disrupt the equilibrium. Option C mentions a founder effect, which can reduce genetic diversity but is not a characteristic of a population in Hardy-Weinberg equilibrium. Option D describes a population dominated by a single homozygous genotype, which also does not align with the genetic diversity seen in a population at Hardy-Weinberg equilibrium.

4. Which hormone is released by the adrenal glands in response to stress?

• A. Insulin
• B. Cortisol
• C. Adrenaline
• D. Glucagon

Correct answer: C

Rationale: Adrenaline is the correct answer. It is released by the adrenal glands in response to stress to prepare the body for the 'fight or flight' response. Adrenaline increases heart rate, dilates airways, and mobilizes energy stores to help the body deal with the perceived threat. Insulin (Choice A) is produced by the pancreas to regulate blood sugar levels, not in response to stress. Cortisol (Choice B) is another hormone released by the adrenal glands in response to stress, but it primarily helps regulate metabolism and immune response. Glucagon (Choice D) is also produced by the pancreas to increase blood sugar levels when they are low, not by the adrenal glands in response to stress.

5. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

• A. By reflecting UV rays away from the skin
• B. By absorbing UV rays and converting them to heat
• C. By blocking UV rays completely
• D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

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