Nursing Elites

1. What event occurs during telophase?

• A. The nuclear envelope disappears.
• B. Organelles double in number.
• C. Chromosomes separate.
• D. Two nuclei are formed.

Correct answer: D

Rationale: During telophase, the final stage of mitosis, the separated chromosomes reach opposite poles of the cell. At this stage, a new nuclear envelope forms around each set of chromosomes, creating two distinct nuclei. This marks the completion of cell division. Choices A, B, and C are incorrect because the disappearance of the nuclear envelope typically occurs during prophase, organelles do not double in number during telophase, and chromosomes separate during anaphase, not telophase.

2. What is the primary function of the endoplasmic reticulum in a cell?

• A. Energy production
• B. Protein synthesis
• C. Waste removal
• D. Transport of materials

Correct answer: D

Rationale: The endoplasmic reticulum's primary function is the transport of materials within the cell. It acts as a network of membranes to assist in the transportation of proteins and other substances throughout the cell. Choice A, 'Energy production,' is incorrect because the endoplasmic reticulum is not directly involved in energy production. Choice B, 'Protein synthesis,' is incorrect as protein synthesis mainly occurs in ribosomes, although the endoplasmic reticulum is involved in modifying and transporting proteins. Choice C, 'Waste removal,' is also incorrect as waste removal is primarily handled by other organelles like lysosomes and peroxisomes.

3. Which structure might be described as a core of nucleic acid surrounded by a protein coat?

• A. RNA
• B. Virus
• C. Blue-green alga
• D. Saprophyte

Correct answer: B

Rationale: A virus can be described as a core of nucleic acid (either RNA or DNA) surrounded by a protein coat, known as a capsid. This structure distinguishes viruses from other microorganisms such as blue-green algae (Cyanobacteria), fungi known as saprophytes, or individual RNA molecules. Viruses depend on a host cell to replicate and are considered non-living entities due to their inability to carry out metabolic functions independently.

4. In order, from lower to upper, the layers of the atmosphere are:

• A. Exosphere, thermosphere, mesosphere, stratosphere, troposphere
• B. Troposphere, stratosphere, mesosphere, thermosphere, exosphere
• C. Mesosphere, troposphere, stratosphere, thermosphere, exosphere
• D. Thermosphere, troposphere, stratosphere, mesosphere, exosphere

Correct answer: B

Rationale: The correct order of the layers of the atmosphere, from lower to upper, is troposphere, stratosphere, mesosphere, thermosphere, exosphere. The troposphere is the lowest layer where weather phenomena occur. The stratosphere contains the ozone layer, which absorbs and scatters the solar ultraviolet radiation. The mesosphere is where most meteorites burn up upon entering the Earth's atmosphere. The thermosphere is characterized by high temperatures due to the absorption of solar radiation. The exosphere is the outermost layer where the atmosphere transitions into space. Therefore, option B is the correct sequence, as it reflects the ascending order of the Earth's atmospheric layers.

5. What happens during the S phase of the cell cycle?

• A. Chromosomes are duplicated.
• B. Cell growth occurs.
• C. DNA is synthesized.
• D. DNA is destroyed.

Correct answer: A

Rationale: During the S phase of the cell cycle, chromosomes are duplicated. This is a critical step in cell division as each chromosome is replicated to ensure that the resulting daughter cells receive an identical set of genetic information. Choices B, C, and D are incorrect because cell growth primarily occurs in the G1 phase, DNA synthesis happens during the S phase, and DNA destruction does not occur during any phase of the cell cycle.

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