Nursing Elites

1. The term that refers to the specific role and position an organism occupies within an ecosystem is called a:

• A. Habitat
• B. Niche
• C. Population
• D. Biome

Correct answer: B

Rationale: A) Habitat refers to the specific physical environment where an organism lives, including the biotic and abiotic factors present. While the habitat is important for an organism's survival, it does not encompass the specific role and interactions of the organism within the ecosystem. B) Niche refers to the specific role and position an organism occupies within an ecosystem, including its interactions with other organisms and its physical environment. This includes the organism's feeding habits, behavior, preferred habitat, and how it obtains resources. The niche of an organism is crucial in determining its impact on the ecosystem and its relationships with other species. C) Population refers to a group of individuals of the same species living in a specific area and interacting with each other. While populations play a role in ecosystems, they do not specifically describe the role and position of an individual organism within the ecosystem. D) Biome refers to a large geographical area characterized by its climate, fauna, and flora. It is a broader concept than niche, habitat, or population, focusing on the overall characteristics of the environment rather than the specific role of an individual organism.

2. Which of the following describes a situation in which research results are consistent with every subsequent experiment, but the test used in the experiment does not measure what it claims to measure?

• A. reliable, but not valid
• B. valid, but not reliable
• C. neither reliable nor valid
• D. both reliable and valid

Correct answer: A

Rationale: The correct answer is A, 'reliable, but not valid.' In this scenario, the research results are consistent in every subsequent experiment, indicating reliability. However, the test used does not measure what it claims to measure, leading to a lack of validity in the results. Choice B, 'valid, but not reliable,' would imply that the test consistently measures what it claims but the results are not consistent, which is not the case here. Choice C, 'neither reliable nor valid,' would suggest that the results are neither consistent nor relevant, which does not align with the provided scenario. Choice D, 'both reliable and valid,' would mean that the results are consistent and measure what they claim to measure, which contradicts the situation described in the question.

3. What are the tiny contractile units within muscle cells called?

• A. Myocytes
• B. Myofibrils
• C. Sarcomeres
• D. Tendons

Correct answer: C

Rationale: Sarcomeres are the smallest contractile units within muscle cells. They consist of overlapping filaments of actin and myosin proteins, which interact to produce muscle contractions. Myocytes are the entire muscle cells, myofibrils are bundles of protein filaments found within muscle cells, and tendons are tough connective tissues that connect muscles to bones. Therefore, sarcomeres specifically represent the contractile units responsible for muscle contraction, making them the correct answer in this context.

4. After a person eats birthday cake, which of the following enzymes is needed to break down the sucrose in the cake?

• A. Lactase
• B. Maltase
• C. Peptidase
• D. Sucrase

Correct answer: D

Rationale: Sucrase is the correct enzyme needed to break down sucrose into its component sugars, glucose, and fructose. Lactase is responsible for breaking down lactose, maltase for maltose, and peptidase for proteins; therefore, they are not the enzymes required to digest sucrose specifically. In the context of digesting birthday cake, which contains sucrose, sucrase is the enzyme needed for this particular sugar.

5. Which nitrogenous bases pair with each other in DNA?

• A. A-G and T-C
• B. A-T and C-G
• C. A-T and T-T
• D. C-C and G-G

Correct answer: B

Rationale: In DNA, nitrogenous bases pair with each other in a specific manner known as complementary base pairing. Adenine (A) always pairs with Thymine (T), and Cytosine (C) always pairs with Guanine (G). This pairing is essential for maintaining the structure and function of DNA. Option B is the correct answer as it correctly identifies the nitrogenous bases that pair with each other in DNA. Choices A, C, and D are incorrect because they do not follow the established base pairing rules in DNA. A-T and C-G are the complementary base pairs in DNA, ensuring the stability and replication fidelity of the genetic material.

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