Nursing Elites

1. 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.

2. What must first occur before a cell can be divided to grow, develop, and reproduce organisms?

• A. RNA replication
• B. DNA replication
• C. Gene replication
• D. Chromosome replication

Correct answer: B

Rationale: The correct answer is B: DNA replication. Before a cell can divide to grow, develop, and reproduce organisms, DNA replication must occur. This process ensures that each daughter cell receives an identical set of genetic information. Choices A, C, and D are incorrect because while RNA, genes, and chromosomes are essential components of cell division, DNA replication is the specific process that must first occur to ensure accurate transmission of genetic material.

3. Why does ice have the capability of floating on water?

• A. It has a higher viscosity
• B. It has a different chemical composition
• C. It has a high specific heat
• D. It forms a lattice when freezing

Correct answer: D

Rationale: The correct answer is D. Ice forms a lattice structure when it freezes, which makes it less dense than liquid water, allowing it to float. Choice A is incorrect because viscosity refers to a fluid's resistance to flow and is not related to ice floating. Choice B is incorrect as ice and liquid water have the same chemical composition (H2O). Choice C is incorrect because the high specific heat of water is not the reason why ice floats.

4. What are the nitrogenous bases of DNA?

• A. Adenine, cytosine, guanine, and thymine
• B. Adenine, guanine, and uracil
• C. Adenine, guanine, and thymine
• D. Adenine, cytosine, guanine, and uracil

Correct answer: A

Rationale: The correct answer is A: Adenine, cytosine, guanine, and thymine. These are the four nitrogenous bases found in DNA. Adenine pairs with thymine, and cytosine pairs with guanine, forming the complementary base pairs in the double helix structure of DNA. Choice B is incorrect because uracil is a nitrogenous base found in RNA, not DNA. Choice C is incorrect as it is missing cytosine, one of the four bases in DNA. Choice D is incorrect because uracil is not a nitrogenous base in DNA, and it also lacks thymine, which is essential for DNA structure.

5. 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.

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