Nursing Elites

1. Which of the following is a common characteristic of alkynes?

• A. They have a triple bond between carbon atoms.
• B. They are saturated hydrocarbons.
• C. They contain only single bonds.
• D. They are aromatic compounds.

Correct answer: A

Rationale: Alkynes are hydrocarbons that contain at least one triple bond between carbon atoms. This triple bond is a distinctive feature of alkynes, distinguishing them from alkanes (which contain only single bonds) and alkenes (which contain at least one double bond). Alkynes are unsaturated hydrocarbons due to the presence of the triple bond. Aromatic compounds, on the other hand, have a specific cyclic structure with resonance stabilization, which is not a characteristic of alkynes.

2. A keystone species plays a critical role in an ecosystem because its removal would:

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Rationale: Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. They play a critical role in maintaining the structure and function of an ecosystem. If a keystone species is removed from an ecosystem, it can disrupt the food web by causing imbalances in predator-prey relationships. This disruption can lead to cascading effects on other populations within the ecosystem, potentially causing population declines or even extinctions. Therefore, the removal of a keystone species would have significant impacts on the overall ecosystem structure, making option D the correct answer.

3. What is the main function of calcitonin, a hormone produced by the thyroid gland?

• A. Stimulate metabolism and heat production
• B. Increase calcium absorption from the intestines
• C. Enhance bone growth and development
• D. Lower blood calcium levels

Correct answer: D

Rationale: The correct answer is D: 'Lower blood calcium levels.' Calcitonin is a hormone produced by the thyroid gland that helps regulate calcium levels in the blood. It works by inhibiting the breakdown of bone, which in turn lowers the amount of calcium released into the bloodstream. This process helps to decrease blood calcium levels when they are too high. Options A, B, and C are not functions of calcitonin; instead, they are more closely associated with other hormones such as thyroid hormones, vitamin D, and growth hormone, respectively.

4. Fertilization, the fusion of sperm and egg, typically occurs in which part of the female reproductive system?

• A. Ovary
• B. Fallopian tube
• C. Uterus
• D. Vagina

Correct answer: B

Rationale: The correct answer is B: Fallopian tube. Fertilization usually occurs in the fallopian tube. After ovulation, the egg is released from the ovary into the fallopian tube where it can be fertilized by sperm. The fallopian tube provides the ideal environment for fertilization to take place before the fertilized egg travels to the uterus for implantation. The other options, such as the ovary, uterus, and vagina, do not typically serve as the site of fertilization. Therefore, the fallopian tube is the correct answer in this case.

5. What type of inheritance pattern results in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation?

• A. Incomplete dominance
• B. Codominance
• C. Sex-linked inheritance
• D. Autosomal dominant inheritance

Correct answer: D

Rationale: Rationale: A) Incomplete dominance: In incomplete dominance, the heterozygous phenotype is a blend of the two homozygous phenotypes. This does not result in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. B) Codominance: In codominance, both alleles are fully expressed in the heterozygous phenotype. This also does not result in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. C) Sex-linked inheritance: Sex-linked inheritance involves genes located on the sex chromosomes and does not typically result in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. D) Autosomal dominant inheritance: In autosomal dominant inheritance, a single copy of the dominant allele is sufficient to express the dominant phenotype. When a heterozygous individual (Aa) is crossed with another

6. The innate immune system provides a non-specific first line of defense. What are some physical barriers that contribute to the innate immune system?

• A. Antibodies
• B. Phagocytes
• C. Skin and mucous membranes
• D. Memory B cells

Correct answer: C

Rationale: The correct answer is C: "Skin and mucous membranes." The innate immune system consists of physical barriers, such as the skin and mucous membranes, that act as the first line of defense against pathogens. These barriers prevent pathogens from entering the body and play a crucial role in protecting against infections. Antibodies (option A) are part of the adaptive immune response, not the innate immune system. Phagocytes (option B) are cells that engulf and destroy pathogens, which are part of the innate immune system. Memory B cells (option D) are specific to the adaptive immune response and are not considered part of the innate immunity that provides the initial, non-specific defense.

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