Nursing Elites

1. Which of the following is the base that will bind with cytosine?

• A. Adenine
• B. Cytosine
• C. Guanine
• D. Thymine

Correct answer: A

Rationale: Adenine is the correct answer as it is the base that binds with cytosine through hydrogen bonding in DNA, forming the A-T base pair. Cytosine always pairs with guanine to form the G-C base pair. Thymine pairs with adenine in DNA, not with cytosine.

2. When is work done on an object?

• A. Only when the object's velocity changes
• B. Only when a force is applied to the object
• C. Whenever there is a force exerted on the object causing displacement
• D. Only when the object is lifted vertically

Correct answer: C

Rationale: Work is done on an object whenever a force causes displacement in the object's position. According to the work-energy principle, work is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Therefore, work can occur whenever there is a force exerted on the object resulting in displacement, regardless of whether the object's velocity changes or it is lifted vertically. Choice A is incorrect because work can be done even without a change in velocity. Choice B is incorrect as work requires both force and displacement, not just the application of force. Choice D is incorrect because work is not limited to vertical lifting; it can happen in any direction as long as there is a force causing displacement.

3. What is the independent variable in this experiment?

• A. Time
• B. Dog weight
• C. Dog species
• D. Dog food type

Correct answer: D

Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.

4. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

5. Which type of immunity does the MMR vaccine provide?

• A. Artificial/active
• B. Artificial/passive
• C. Natural/active
• D. Natural/passive

Correct answer: A

Rationale: The correct answer is A: Artificial/active. The MMR vaccine provides artificial/active immunity. It works by introducing a weakened or killed form of the virus to trigger the body's immune response, leading to the production of antibodies that offer long-lasting protection against measles, mumps, and rubella. Artificial immunity is obtained through medical intervention, such as vaccination, while active immunity involves the immune system's direct response to an antigen. Choices B, C, and D are incorrect because the MMR vaccine does not provide passive immunity nor is it acquired naturally; instead, it stimulates the body to actively produce its immune response.

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