Nursing Elites

1. Which is not part of a nucleic acid?

• A. Sulfate
• B. Phosphate
• C. Carbon
• D. Nitrogen

Correct answer: A

Rationale: Sulfate is not part of a nucleic acid. Nucleic acids, such as DNA and RNA, are composed of nucleotide units, which consist of a phosphate group, a sugar molecule (ribose in RNA and deoxyribose in DNA), and a nitrogenous base. Carbon and nitrogen are essential elements found in nucleic acids, while sulfate is not a component of nucleic acid structure. Therefore, the correct answer is A: Sulfate.

2. What process involves the movement of water molecules through a selectively permeable membrane?

• A. Diffusion
• B. Osmosis
• C. Active Transport
• D. Facilitated Diffusion

Correct answer: B

Rationale: Osmosis is the process specifically involving the movement of water molecules through a selectively permeable membrane, from an area of higher water concentration to an area of lower water concentration. This process helps balance concentrations on both sides of the membrane. Choice A, Diffusion, refers to the movement of particles from an area of higher concentration to an area of lower concentration, not specific to water. Choice C, Active Transport, requires energy to move substances against their concentration gradient, unlike osmosis. Choice D, Facilitated Diffusion, involves the use of transport proteins to move specific substances across membranes, not limited to water molecules.

3. 72 chromosomes undergo meiosis. How many chromosomes will be in each gamete?

• A. 18
• B. 36
• C. 72
• D. 144

Correct answer: A

Rationale: During meiosis, the number of chromosomes is halved in each gamete. Since 72 chromosomes undergo meiosis, each gamete will contain half of that number, which is 36 chromosomes. Therefore, the correct answer is 18 chromosomes in each gamete. Choice B (36 chromosomes) is incorrect because it represents the total number of chromosomes that undergo meiosis, not the number in each gamete. Choice C (72 chromosomes) is incorrect as it represents the initial number of chromosomes, not the number in each gamete after meiosis. Choice D (144 chromosomes) is incorrect as it doubles the initial number of chromosomes, which is not the outcome of meiosis.

4. Why can animal cells use a contractile ring but plant cells cannot?

• A. Plant cells can use both methods to divide
• B. Animal cells divide faster, requiring them to pinch apart
• C. Plant cells are too rigid to use a contractile ring
• D. N/A

Correct answer: C

Rationale: Plant cells have a rigid cell wall surrounding them, which prevents them from using a contractile ring for cell division. The rigid cell wall requires plant cells to form a cell plate during cell division instead of pinching apart like animal cells with a contractile ring. Choice A is incorrect because plant cells cannot use a contractile ring due to their rigid cell wall. Choice B is incorrect as the speed of cell division is not the primary reason for the difference in cell division mechanisms between plant and animal cells. Choice D is not applicable as plant cells indeed have a specific limitation in using a contractile ring for cell division.

5. What type of cells possess a cell membrane?

• A. Prokaryotic cells only
• B. Eukaryotic cells only
• C. Both prokaryotic and eukaryotic cells
• D. None of the above

Correct answer: C

Rationale: Cell membranes are present in both prokaryotic and eukaryotic cells. The cell membrane serves as a barrier that encloses the cell contents and regulates the entry and exit of substances in and out of the cell. It is a fundamental structure found in all types of cells, regardless of whether they are prokaryotic (lacking a nucleus) or eukaryotic (containing a nucleus). Choice A is incorrect because eukaryotic cells also possess cell membranes. Choice B is incorrect as prokaryotic cells, such as bacteria, also have cell membranes. Choice D is incorrect as both prokaryotic and eukaryotic cells have cell membranes.

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