Nursing Elites

1. Bacillus subtilis may be described as ___________.

• A. spiral
• B. globular
• C. rod-shaped
• D. grape-like clusters

Correct answer: C

Rationale: Bacillus subtilis is a rod-shaped bacterium. Its name "Bacillus" refers to its rod-like shape, which is a characteristic feature of this bacteria.

2. 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.

3. 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.

4. What happens to messenger RNA when it reaches the cytoplasm?

• A. It attaches to a ribosome.
• B. It unzips, exposing nitrogen bases.
• C. It pairs with the DNA bases.
• D. It pulls free of the DNA strand.

Correct answer: A

Rationale: Messenger RNA (mRNA) carries genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm. When mRNA reaches the cytoplasm, it attaches to a ribosome. The ribosome functions as the site for protein synthesis through translation, where the genetic code carried by mRNA is read and translated into a specific sequence of amino acids. Choices B, C, and D are incorrect because mRNA does not unzip, expose nitrogen bases, pair with DNA bases, or pull free of the DNA strand in the cytoplasm. The primary function of mRNA in the cytoplasm is to serve as a template for protein synthesis by binding to ribosomes.

5. Which organelle is responsible for organizing protein synthesis?

• A. Nucleus
• B. Ribosome
• C. Lysosome
• D. Vacuole

Correct answer: B

Rationale: The correct answer is B: Ribosome. Ribosomes are responsible for organizing protein synthesis by assembling amino acids. They are the cellular machinery where proteins are synthesized. The other choices, such as the nucleus, lysosome, and vacuole, do not directly participate in protein synthesis. The nucleus contains DNA and controls cell activities, the lysosome is involved in digestion and waste removal, and the vacuole is responsible for storage and maintaining cell turgor pressure.

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