Nursing Elites

1. Which of the following statements is most accurate regarding the transcription of DNA?

• A. RNA uses reverse transcriptase to make mRNA
• B. DNA uses mRNA to produce tRNA
• C. RNA creates a duplicate copy of DNA
• D. RNA copies DNA to produce mRNA

Correct answer: D

Rationale: The correct answer is D. During transcription, RNA copies DNA to produce mRNA, which carries the genetic information from DNA to the ribosomes for protein synthesis. Choice A is incorrect because reverse transcriptase is not involved in the transcription of DNA. Choice B is incorrect as DNA does not use mRNA to produce tRNA; tRNA is produced through a different process. Choice C is incorrect as RNA does not create a duplicate copy of DNA during transcription; it synthesizes mRNA by copying the DNA template.

2. What is the composition of the cellular membrane?

• A. A bilayer of phospholipid molecules
• B. A single layer of phospholipid molecules
• C. Proteins that act as transport highways
• D. Carbohydrates

Correct answer: A

Rationale: The cellular membrane is primarily composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules. These molecules have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tail, creating a barrier that separates the internal cellular environment from the external surroundings. While proteins are embedded within this bilayer and act as transport channels, receptors, and structural support, carbohydrates are found on the outer surface of the membrane for cell recognition and signaling purposes. Therefore, the correct answer is a bilayer of phospholipid molecules.

3. What do prokaryotic cells lack in comparison to eukaryotic cells?

• A. A defined nucleus and a series of membrane-bound organelles
• B. A defined nucleus and no membrane-bound organelles
• C. No defined nucleus and a series of membrane-bound organelles
• D. No defined nucleus and no membrane-bound organelles

Correct answer: D

Rationale: Prokaryotic cells are characterized by the absence of a defined nucleus and membrane-bound organelles. Choice A is incorrect because prokaryotic cells lack membrane-bound organelles. Choice B is incorrect because prokaryotic cells lack both a defined nucleus and membrane-bound organelles. Choice C is incorrect as prokaryotic cells have no defined nucleus. Therefore, the correct answer is D.

4. Which of the following molecules acts as the genetic code's messenger?

• A. RNA
• B. Proteins
• C. DNA
• D. Carbohydrates

Correct answer: A

Rationale: The correct answer is RNA. RNA, particularly mRNA, serves as the messenger that carries genetic information from DNA to the ribosome, where proteins are synthesized. Proteins (choice B) are not the genetic code's messenger; they are synthesized based on the information carried by RNA. DNA (choice C) stores the genetic information but does not directly act as the messenger. Carbohydrates (choice D) are not involved in transmitting genetic information.

5. During which stage of mitosis do the chromosomes gather on either side of the separating cell?

• A. Metaphase
• B. Telophase
• C. Anaphase
• D. Prophase

Correct answer: B

Rationale: The correct answer is B, Telophase. During telophase, the chromosomes gather at opposite poles of the cell as the nuclear envelopes start to form around them, indicating the end of cell division. Choices A, C, and D are incorrect because during metaphase, the chromosomes align in the middle of the cell; in anaphase, the chromosomes separate and move towards opposite poles; and in prophase, the chromosomes condense and the nuclear envelope breaks down, respectively.

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