Nursing Elites

1. How many different types of nucleotides are there in DNA?

• A. one
• B. two
• C. four
• D. eight

Correct answer: C

Rationale: The correct answer is 'C: four.' DNA is composed of four different types of nucleotides: adenine, thymine, guanine, and cytosine. These nucleotides pair up in specific combinations to form the genetic code. Choices 'A: one,' 'B: two,' and 'D: eight' are incorrect because DNA consists of a set of four distinct nucleotides, not one, two, or eight.

2. Which, if any, of the following statements about the biosphere is correct?

• A. The biosphere is the part of the Earth that supports life.
• B. The biosphere encompasses the entire surface of the Earth.
• C. A and B are correct.
• D. None of these statements is correct.

Correct answer: A

Rationale: Statement A is correct. The biosphere refers to the part of the Earth where life exists, including the land, water bodies, and atmosphere. It is the zone where living organisms and ecosystems exist. Statement B is incorrect because the biosphere covers various ecosystems on Earth but does not encompass the entire surface of the planet. The biosphere includes regions such as the lithosphere (land), hydrosphere (water bodies), and atmosphere, but not every part of the Earth's surface. Therefore, option C, stating both A and B are correct, is inaccurate. The correct answer is option A, as it accurately defines the biosphere.

3. Which of the following structures is not directly involved in translation?

• A. tRNA
• B. mRNA
• C. ribosome
• D. DNA

Correct answer: D

Rationale: The correct answer is 'D: DNA.' DNA is not directly involved in translation, which is the process of synthesizing proteins from mRNA. tRNA carries amino acids to the ribosome, mRNA provides the template for protein synthesis, and ribosomes are the cellular machinery where translation occurs. DNA's main role is in transcription, where it serves as the template for mRNA synthesis, not in translation.

4. Why does cytokinesis happen?

• A. DNA can duplicate
• B. Organelles can convert energy
• C. Bacteria can be killed
• D. Daughter cells can divide

Correct answer: D

Rationale: Cytokinesis happens at the end of mitosis to physically separate the newly formed daughter cells. This allows the cell to divide into two separate daughter cells, each containing a complete set of genetic material (DNA) and organelles. The purpose of cytokinesis is to ensure that each daughter cell receives the necessary components to function independently. Choices A, B, and C are incorrect because cytokinesis does not directly involve DNA duplication, organelles converting energy, or killing bacteria.

5. Which is an example of a gymnosperm?

• A. Red cedar
• B. Japanese cherry
• C. Flowering dogwood
• D. American chestnut

Correct answer: A

Rationale: Red cedar is the correct answer as it is an example of a gymnosperm. Gymnosperms are plants that produce seeds not enclosed within an ovary or fruit. In the case of red cedar, it belongs to the gymnosperm group and has naked seeds that are exposed on the surface of scales or leaves. Choices B, C, and D are angiosperms, not gymnosperms. Japanese cherry, flowering dogwood, and American chestnut are all examples of angiosperms, which are flowering plants with seeds enclosed within an ovary.

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