Nursing Elites

1. Which of the following do prokaryotic cells lack?

• A. A cell membrane
• B. Genetic material
• C. Cytoplasm
• D. Membrane-bound organelles

Correct answer: D

Rationale: The correct answer is D: Prokaryotic cells lack membrane-bound organelles, such as mitochondria or a nucleus, distinguishing them from eukaryotic cells. Prokaryotic cells do have genetic material, a cell membrane, and cytoplasm. Choice A is incorrect because prokaryotic cells do have a cell membrane, which is essential for maintaining cell structure and regulating what enters and exits the cell. Choice B is incorrect because prokaryotic cells contain genetic material, typically in the form of a single circular chromosome. Choice C is incorrect because prokaryotic cells have cytoplasm, where various cellular activities take place.

2. What function does cholesterol, a phospholipid, serve within the cell membrane?

• A. It builds up fats to make the structure more flexible
• B. It allows protein channels to form
• C. It makes the structure very rigid and impermeable
• D. It stabilizes the membrane structure

Correct answer: D

Rationale: Cholesterol helps to maintain the fluidity and stability of the cell membrane by fitting between the phospholipid molecules. Choice A is incorrect because cholesterol does not build up fats in the cell membrane. Choice B is incorrect as protein channels are formed by proteins, not cholesterol. Choice C is incorrect as cholesterol actually helps regulate the fluidity of the membrane, making it less rigid and more permeable.

3. What percentage of the parents' offspring is predicted to have a cleft chin if one parent carries the recessive gene for a cleft chin (c) while the other parent does not?

• A. 25%
• B. 50%
• C. 0%
• D. 75%

Correct answer: C

Rationale: The correct answer is C (0%). If one parent carries the recessive gene for a cleft chin while the other parent does not carry it, none of their offspring is predicted to have a cleft chin. This is because the cleft chin trait is recessive, so for an offspring to express this trait, they would need to inherit the gene from both parents. In this scenario, none of the offspring will inherit the recessive gene from both parents, so the percentage of offspring predicted to have a cleft chin is 0%. Choices A, B, and D are incorrect because in this situation, the offspring will not express the cleft chin phenotype, although they could be carriers of the recessive gene.

4. 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.

5. Water is a polar molecule that can be:

• A. cohesive and corrosive
• B. cohesive and adhesive
• C. electrostatic and ionic
• D. repellent and attractive

Correct answer: B

Rationale: Water is a polar molecule due to an uneven distribution of electrons, allowing it to form hydrogen bonds. This property makes water both cohesive (attracted to itself) and adhesive (attracted to other substances). Choice A is incorrect because water is not corrosive; rather, it is a solvent. Choices C and D are incorrect as they do not describe the cohesive and adhesive properties of water.

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