Nursing Elites

1. Which of the following is directly transcribed from DNA and represents the first step in protein synthesis?

• A. siRNA
• B. rRNA
• C. mRNA
• D. tRNA

Correct answer: C

Rationale: mRNA (messenger RNA) is directly transcribed from DNA in the nucleus during the process of transcription. It serves as a template for protein synthesis during translation in the cytoplasm. mRNA carries genetic information from the DNA to the ribosomes, where it determines the sequence of amino acids in a protein. Thus, mRNA represents the first step in protein synthesis as it carries the code from the DNA to be translated into a protein. Choice A, siRNA (small interfering RNA), is involved in post-transcriptional gene silencing and does not play a role in protein synthesis. Choice B, rRNA (ribosomal RNA), is a component of the ribosome and plays a structural and functional role in protein synthesis but is not directly transcribed from DNA. Choice D, tRNA (transfer RNA), is responsible for bringing amino acids to the ribosome during protein synthesis but is not directly transcribed from DNA.

2. A car brakes to a stop on a level road. Which of the following forces does NOT do work on the car?

• A. The braking force applied by the wheels
• B. The normal force from the road
• C. The gravitational force on the car
• D. The friction force between the tires and the road

Correct answer: B

Rationale: The normal force from the road does not do work on the car because it is perpendicular to the direction of motion. Work is defined as force applied in the direction of motion, so the normal force, which acts perpendicular to the motion of the car, does not contribute to the work done on the car. The braking force applied by the wheels, the gravitational force on the car, and the friction force between the tires and the road all act in the direction of motion and contribute to the work done on the car. In this scenario, the normal force is supporting the weight of the car and keeping it from sinking into the road, but it does not transfer energy to the car as it moves.

3. In the K-capture process, a type of electron capture, from which electron shell does the electron get captured?

• A. The outermost s-orbital
• B. An inner p-orbital
• C. An inner d-orbital
• D. Any available electron shell

Correct answer: B

Rationale: The K-capture process involves the capture of an electron from the innermost electron shell, known as the K-shell. The K-shell comprises s and p orbitals. During the K-capture process, an electron is specifically captured from an inner p-orbital within the K-shell. Choices A, C, and D are incorrect because K-capture involves capturing an electron from the innermost shell (K-shell) which consists of s and p orbitals, not the outermost s-orbital, inner d-orbital, or any available electron shell.

4. What is the difference between a ventral and dorsal root of a spinal nerve?

• A. Ventral carries motor, dorsal carries sensory information.
• B. Ventral carries sensory, dorsal carries motor information.
• C. Ventral is larger, dorsal is smaller.
• D. Ventral is located anteriorly, dorsal is posteriorly.

Correct answer: A

Rationale: The correct answer is A: Ventral carries motor, dorsal carries sensory information. In the spinal nerve, the ventral root carries motor information from the spinal cord to the muscles, while the dorsal root carries sensory information from the peripheral sensory receptors to the spinal cord. Therefore, other choices are incorrect. Choice B is incorrect as it states the opposite roles of ventral and dorsal roots. Choice C is incorrect as the size comparison between ventral and dorsal roots is not related to their functions. Choice D is incorrect as the terms 'anteriorly' and 'posteriorly' are not commonly used to describe the locations of ventral and dorsal roots in relation to each other.

5. When sugar is heated, it breaks down into carbon and water vapor. This is an example of a:

• A. Combination reaction
• B. Decomposition reaction
• C. Double displacement reaction
• D. Single displacement reaction

Correct answer: B

Rationale: The correct answer is B: Decomposition reaction. When sugar is heated, it undergoes a decomposition reaction where it breaks down into simpler substances, carbon, and water vapor. In a decomposition reaction, a single compound breaks down into two or more simpler substances. This process is the opposite of a combination reaction where two or more substances combine to form a new compound. Choice A, Combination reaction, is incorrect because a combination reaction involves the combination of two or more substances to form a new compound, which is the opposite of what happens when sugar breaks down. Choices C and D, Double displacement reaction and Single displacement reaction, are incorrect as they involve different mechanisms where the atoms or ions of the reactants are exchanged, which is not the case in the breakdown of sugar into carbon and water vapor.

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