Nursing Elites

1. The 'fight-or-flight' response is triggered by the hormone released from the:

• A. Thyroid gland
• B. Adrenal glands
• C. Pituitary gland
• D. Pancreas

Correct answer: B

Rationale: The 'fight-or-flight' response is triggered by the release of adrenaline (epinephrine) and norepinephrine from the adrenal glands. These hormones prepare the body to either confront or flee from a perceived threat or stressor. The adrenal glands are crucial in initiating this rapid physiological response. Choices A, C, and D are incorrect because the thyroid gland primarily regulates metabolism and energy levels, the pituitary gland controls other endocrine glands but does not directly trigger the 'fight-or-flight' response, and the pancreas is responsible for regulating blood sugar levels through insulin and glucagon, not for triggering the 'fight-or-flight' response.

2. What is the small repeating unit in the contractile apparatus of skeletal muscle?

• A. Myofibril
• B. Actin
• C. Sarcomere
• D. Myosin

Correct answer: C

Rationale: The correct answer is 'Sarcomere.' The sarcomere is the smallest repeating unit within myofibrils and is responsible for muscle contraction in skeletal muscle. It consists of overlapping actin and myosin filaments arranged in a highly organized structure that allows for the sliding of filaments during muscle contraction. 'Myofibril' (choice A) is incorrect because it is a larger structure composed of sarcomeres. 'Actin' (choice B) and 'Myosin' (choice D) are incorrect as they are individual proteins that are components of the sarcomere, not the smallest repeating unit itself.

3. What scientific term encompasses a permanent alteration in the DNA sequence?

• A. Trait
• B. Mutation
• C. Allele
• D. Variation

Correct answer: B

Rationale: A) Trait: A trait is a characteristic or feature of an organism that is determined by its genes. B) Mutation: A mutation is a permanent alteration in the DNA sequence that can result from errors during DNA replication, exposure to mutagens, or other factors. C) Allele: An allele is a variant form of a gene that can result in different traits or characteristics. D) Variation: Variation refers to the differences in traits or characteristics among individuals of the same species, which can be influenced by genetic and environmental factors. In this context, the term that specifically refers to a permanent alteration in the DNA sequence is "mutation."

4. How can a single gene mutation lead to multiple phenotypes depending on the organism?

• A. Pleiotropy describes the effect of one gene influencing multiple seemingly unrelated traits.
• B. Epigenetics involves environmental factors modifying gene expression without altering the DNA sequence.
• C. Genetic drift refers to random changes in allele frequencies within a population.
• D. Gene regulation controls the timing and level of gene expression within an organism.

Correct answer: A

Rationale: A single gene mutation can lead to multiple phenotypes through pleiotropy, where one gene influences diverse traits or functions in an organism. This phenomenon occurs when the mutated gene affects different biochemical pathways, developmental processes, or cellular functions, resulting in a cascade of downstream effects that manifest as a variety of phenotypic outcomes. Choice B, epigenetics, involves modifications in gene expression influenced by environmental factors without altering the DNA sequence, which is not directly related to the question about single gene mutations causing multiple phenotypes. Choice C, genetic drift, refers to random changes in allele frequencies within a population, which is unrelated to the impact of a single gene mutation on multiple phenotypes. Choice D, gene regulation, focuses on controlling the timing and level of gene expression within an organism, which is not directly addressing how a single gene mutation can lead to diverse phenotypes.

5. Which organ of the body compensates when a person's intake of vitamins decreases?

• A. Appendix
• B. Liver
• C. Pancreas
• D. Stomach

Correct answer: B

Rationale: The liver is the organ that compensates when a person's intake of vitamins decreases. It stores certain vitamins, such as vitamins A, D, E, K, and B12, and releases them when dietary intake decreases. This helps maintain the body's vitamin levels and functions. The other organs listed - Appendix, Pancreas, and Stomach - do not primarily play a role in compensating for a decrease in vitamin intake. The liver is crucial in maintaining vitamin balance, making it the correct choice in this context.

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