Nursing Elites

1. What is the difference between polygenic inheritance and pleiotropy?

• A. Polygenic inheritance involves multiple genes influencing one trait, while pleiotropy involves one gene affecting multiple traits.
• B. Polygenic inheritance is found in simple Mendelian traits, while pleiotropy is found in complex traits.
• C. Polygenic inheritance is always quantitative, while pleiotropy can be qualitative or quantitative.
• D. Both involve multiple genes and multiple traits, but the specific mechanisms differ

Correct answer: A

Rationale: - Polygenic inheritance refers to the situation where a trait is influenced by multiple genes, each contributing a small effect to the phenotype. These traits often show continuous variation and are not easily categorized into discrete categories. - Pleiotropy, on the other hand, occurs when a single gene influences multiple, seemingly unrelated traits. This means that a mutation in one gene can lead to multiple phenotypic effects across different traits or characteristics. - Therefore, the key difference between polygenic inheritance and pleiotropy lies in the number of genes involved in influencing a trait (multiple genes in polygenic inheritance vs. one gene in pleiotropy) and the direction of influence (one trait affected by multiple genes in polygenic inheritance vs. multiple traits affected by one gene in pleiotropy).

2. How many pairs of chromosomes are in a human cell?

• A. 46
• B. 23
• C. 64
• D. 32

Correct answer: B

Rationale: The correct answer is B: 23. Humans have 23 pairs of chromosomes, totaling 46 chromosomes. Each pair consists of one chromosome inherited from the mother and one from the father, making a total of 46 chromosomes in a human cell. Choice A (46) is incorrect as it represents the total number of chromosomes, not pairs. Choice C (64) and D (32) are incorrect as they do not reflect the accurate number of chromosome pairs in a human cell.

3. 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.

4. Which property of a substance refers to its ability to be stretched into thin wires?

• A. Conductivity
• B. Viscosity
• C. Ductility
• D. Malleability

Correct answer: C

Rationale: Ductility is the property of a substance that allows it to be stretched into thin wires without breaking. It is a crucial property for materials used in wire production. Conductivity refers to the ability of a substance to conduct electricity or heat, not to be stretched into wires. Viscosity is the measure of a fluid's resistance to flow, not its ability to be stretched. Malleability is the property of a substance that allows it to be hammered or rolled into thin sheets, not stretched into wires.

5. A car is moving in a circle at a constant speed. Which of the following is NOT true about its motion?

• A. It has a constant centripetal acceleration
• B. Its tangential velocity remains constant
• C. It experiences a force directed towards the center of the circle
• D. It covers the same distance in equal time intervals along its circular path

Correct answer: B

Rationale: In circular motion at a constant speed, the car has a constant centripetal acceleration (choice A), experiences a force directed towards the center of the circle (choice C), and covers the same distance in equal time intervals along its circular path (choice D). However, the tangential velocity of an object in circular motion at a constant speed changes continuously as it moves around the circle, so it is not constant (choice B). The change in tangential velocity allows the car to maintain its motion in a circular path despite moving at a constant speed. Choice A is incorrect because centripetal acceleration is indeed present to keep the car moving in a circular path. Choice C is incorrect as a force towards the center is required to keep the car in circular motion. Choice D is incorrect because the car covers equal distances in equal time intervals to maintain its circular trajectory.

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