Nursing Elites

1. A 10 kg box rests on a frictionless surface. A horizontal force of 20 N is applied to the box. What is the box's acceleration?

• A. 0.5 m/s²
• B. 1 m/s²
• C. 2 m/s²
• D. 10 m/s²

Correct answer: B

Rationale: The acceleration of an object is given by the formula \(a = \frac{F}{m}\), where \(F\) is the net force acting on the object and \(m\) is the mass of the object. In this case, the net force acting on the box is 20 N, and the mass of the box is 10 kg. Plugging these values into the formula, we get \(a = \frac{20}{10} = 2\) m/s².

2. Which vitamin plays a crucial role in calcium absorption in the small intestine?

• A. Vitamin A
• B. Vitamin C
• C. Vitamin D
• D. Vitamin E

Correct answer: C

Rationale: The correct answer is Vitamin D. Vitamin D plays a crucial role in calcium absorption in the small intestine by enhancing the absorption of calcium and phosphorus. This helps in regulating the levels of these minerals in the body, which are essential for maintaining healthy bones. Vitamin A (Choice A) is important for vision and immune function, but it is not directly related to calcium absorption. Vitamin C (Choice B) is primarily known for its role in collagen synthesis and antioxidant functions, not calcium absorption. Vitamin E (Choice D) acts as an antioxidant and is not directly involved in calcium absorption in the small intestine.

3. A person pushes a box across a floor with a constant force. The box eventually comes to a stop due to friction. What happens to the work done by the person?

• A. It increases as the box moves further.
• B. It decreases as the box slows down.
• C. It remains constant throughout the motion.
• D. It becomes zero once the box stops.

Correct answer: D

Rationale: Work done is defined as the product of the force applied and the distance moved in the direction of the force. In this scenario, when the box comes to a stop, the displacement becomes zero, leading to zero work done by the person. Choice A is incorrect as the work done is not increasing, but rather decreasing as the box slows down. Choice B is incorrect because the work done does not decrease as the box slows down; it becomes zero when the box stops. Choice C is incorrect as the work done is not constant but decreases to zero when the box stops.

4. Which level of protein structure is defined by the folds and coils of the protein's polypeptide backbone?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Quaternary

Correct answer: B

Rationale: The correct answer is B: Secondary. The secondary structure of a protein is defined by the folds and coils of the protein's polypeptide backbone. This level of structure is characterized by the formation of alpha helices and beta sheets, which are stabilized by hydrogen bonds between amino acids along the polypeptide chain. Choice A, Primary, refers to the linear sequence of amino acids in the protein. Choice C, Tertiary, involves the 3D folding of the entire polypeptide chain. Choice D, Quaternary, pertains to the arrangement of multiple polypeptide subunits in a protein complex.

5. What is the name of the regulatory region in a gene that controls its expression?

• A. Exon
• B. Intron
• C. Promoter
• D. Enhancer

Correct answer: C

Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.

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