Nursing Elites

1. 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.

2. Which of the following body systems controls fluid loss, protects deep tissues, and synthesizes vitamin D?

• A. The skeletal system
• B. The muscular system
• C. The lymphatic system
• D. The integumentary system

Correct answer: D

Rationale: The integumentary system is responsible for controlling fluid loss through sweat, protecting deep tissues as the body's first line of defense, and synthesizing vitamin D when exposed to sunlight. The skin, hair, nails, and associated glands make up the integumentary system, which plays a crucial role in maintaining homeostasis and overall health. The skeletal system (Choice A) provides structural support and protection for internal organs but does not directly control fluid loss, protect deep tissues, or synthesize vitamin D. The muscular system (Choice B) is responsible for movement and stability but is not involved in the functions described. The lymphatic system (Choice C) is primarily responsible for immunity and fluid balance, not the specific functions mentioned in the question.

3. Two objects with equal masses collide head-on, both initially moving at the same speed. After the collision, they stick together. What is their final velocity?

• A. Zero
• B. Half their initial velocity
• C. Their initial velocity
• D. Twice their initial velocity

Correct answer: C

Rationale: In an inelastic collision where two objects stick together after colliding, momentum is conserved. Since the two objects have equal masses and equal initial velocities but opposite directions, their momenta cancel out. Therefore, after the collision, the combined mass will move at the same speed as the initial velocity, but in the direction of one of the objects. Choice A ('Zero') is incorrect because momentum is conserved, and the objects must move after the collision. Choice B ('Half their initial velocity') is incorrect as the final velocity is the same as the initial velocity due to momentum conservation. Choice D ('Twice their initial velocity') is incorrect as the final velocity cannot be twice the initial velocity based on the conservation of momentum principle.

4. Where is the gastrocnemius vein in relation to the femoral vein?

• A. Lateral
• B. Distal
• C. Superior
• D. Ventral

Correct answer: A

Rationale: The gastrocnemius vein is located lateral to the femoral vein. In anatomical terms, lateral refers to the direction towards the side of the body or away from the midline. In this case, the gastrocnemius vein is positioned to the side of the femoral vein. The term 'distal' refers to being further away from the point of reference, 'superior' indicates a higher position, and 'ventral' refers to the front or anterior aspect of the body. Therefore, the correct answer is A. Lateral.

5. What macromolecules are formed from amino acids, and what are their roles?

• A. Lipids; store energy
• B. Carbohydrates; provide energy
• C. Proteins; perform various functions like catalysis, transport, and structural support
• D. Nucleic acids; store genetic information

Correct answer: C

Rationale: The correct answer is C. Proteins are macromolecules formed from amino acids and have diverse roles, such as serving as enzymes, transport molecules, and providing structural support. They are essential for catalysis, cellular communication, immune response, and many other functions in living organisms. Choices A, B, and D are incorrect. Lipids are not formed from amino acids but from fatty acids and glycerol, mainly serving as energy storage molecules. Carbohydrates are composed of sugars and provide energy to the body. Nucleic acids, like DNA and RNA, are made up of nucleotides and store genetic information in cells.

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