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. What controls muscles by sending electrical impulses to the muscles?

• A. Blood vessels
• B. Nerves
• C. Hormones
• D. Neurons

Correct answer: B

Rationale: Nerves control muscles by transmitting electrical impulses that initiate muscle contractions. Blood vessels are responsible for transporting blood, not controlling muscles. Hormones are chemical messengers produced by glands to regulate bodily functions, not specifically controlling muscles. Neurons are the basic building blocks of the nervous system that transmit signals, but nerves are the specific structures that control muscles by sending electrical impulses.

3. What is the diastole cycle in the heart?

• A. Relaxation of the heart
• B. Contraction of the heart
• C. Pulse rate of the heart
• D. Blood circulation

Correct answer: A

Rationale: The diastole cycle in the heart refers to the relaxation phase, where the heart chambers relax and fill with blood. This phase is crucial for the heart to refill and prepare for the next contraction (systole), which pumps blood out of the heart. Therefore, the correct answer is choice A, 'Relaxation of the heart.' Choices B, C, and D are incorrect in the context of cardiac physiology. Choice B, 'Contraction of the heart,' refers to systole, the phase of heart contraction. Choice C, 'Pulse rate of the heart,' is related to the number of heartbeats per minute, not the diastole cycle specifically. Choice D, 'Blood circulation,' is a broader term that encompasses the entire circulatory system rather than focusing on the heart's specific relaxation phase.

4. If the mass of an object remains constant and its velocity doubles, how does its momentum change?

• A. Momentum doubles
• B. Momentum halves
• C. Momentum quadruples
• D. Momentum remains the same

Correct answer: C

Rationale: Momentum is calculated as the product of an object's mass and its velocity. When the mass remains constant and the velocity doubles, the momentum will increase by a factor of 2 (doubling) due to the increase in velocity. Therefore, the momentum will quadruple (2 x 2 = 4) when the velocity doubles. This relationship between momentum and velocity showcases the direct proportionality of momentum to velocity, given a constant mass. Choices A, B, and D are incorrect. Momentum does not simply double or halve when the velocity doubles; it quadruples as it is directly proportional to the velocity. Hence, the correct answer is C, where momentum quadruples in this scenario.

5. What is the process of making copies of RNA from DNA called?

• A. Replication
• B. Transcription
• C. Translation
• D. DNA repair

Correct answer: B

Rationale: Transcription is the correct answer. Transcription is the process of making copies of RNA from DNA. During transcription, the enzyme RNA polymerase binds to a specific region of DNA and synthesizes a complementary RNA strand based on the DNA template. This process is essential for gene expression and protein synthesis in cells. Replication (option A) refers to the process of making copies of DNA, not RNA. Translation (option C) is the process of synthesizing proteins from mRNA, not making copies of RNA from DNA. DNA repair (option D) involves mechanisms that cells use to repair damaged DNA, not the process of making RNA copies from DNA.

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