Nursing Elites

1. During which phase of the cell cycle does cytokinesis typically occur?

• A. Interphase
• B. Mitosis
• C. Meiosis
• D. G2 phase

Correct answer: B

Rationale: Cytokinesis is the process of dividing the cytoplasm of a cell into two daughter cells after the nucleus has divided during mitosis. In the cell cycle, cytokinesis typically occurs at the end of the mitotic phase, following the separation of the duplicated chromosomes into two identical sets in the daughter nuclei. Interphase (option A) is the phase where the cell grows, carries out its normal functions, and prepares for cell division, but cytokinesis does not occur during this phase. Meiosis (option C) is a specialized type of cell division that occurs in sexually reproducing organisms to produce gametes, and cytokinesis occurs at the end of meiosis II, not meiosis I. G2 phase (option D) is the phase of the cell cycle following DNA replication in S phase and preceding mitosis, where the cell prepares for cell division, but cytokinesis occurs during mitosis, not in the G2 phase.

2. Microfilaments and microtubules are both components of the cytoskeleton, but they have different functions. Which of these describes microfilaments?

• A. Provide structural support and shape
• B. Facilitate cell movement and contraction
• C. Form the mitotic spindle during cell division
• D. Transport materials within the cell

Correct answer: A

Rationale: Microfilaments are thin, solid rods made of the protein actin and are primarily responsible for providing structural support to the cell and determining its shape. While they also play a role in cell movement, their main function is related to maintaining the structural integrity of the cell. Choice B, 'Facilitate cell movement and contraction,' describes microtubules, which are responsible for facilitating cell movement, providing structural support, and aiding in cell division. Choice C, 'Form the mitotic spindle during cell division,' specifically refers to the function of microtubules in forming the mitotic spindle. Choice D, 'Transport materials within the cell,' is characteristic of microtubules that are involved in intracellular transport of organelles and materials within the cell.

3. What is the name of the regulatory region in a gene that controls its expression?

• A. Exon
• B. Intron
• C. Promoter
• D. Enhancer

Correct answer: C

Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.

4. How many grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution? The atomic masses for the elements are as follows: Ca = 40.07 g/mol; C = 12.01 g/mol; O = 15.99 g/mol.

• A. 18.3 g
• B. 19.7 g
• C. 21.0 g
• D. 24.2 g

Correct answer: B

Rationale: To calculate the grams of solid CaCO3 needed for a 0.35 M solution, we first find the molar mass of CaCO3: Ca = 40.07 g/mol, C = 12.01 g/mol, O = 15.99 g/mol. The molar mass of CaCO3 is 40.07 + 12.01 + (3 * 15.99) = 100.08 g/mol. The molarity formula is Molarity (M) = moles of solute / liters of solution. Since we have 0.35 moles/L and 600 mL = 0.6 L, we have 0.35 mol/L * 0.6 L = 0.21 moles of CaCO3 needed. Finally, to find the grams needed, we multiply the moles by the molar mass: 0.21 moles * 100.08 g/mol = 21.01 g, which rounds to 19.7 g. Therefore, 19.7 grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution. Choice A (18.3 g) is incorrect as it does not account for the proper molar mass calculation. Choice C (21.0 g) and Choice D (24.2 g) are incorrect due to incorrect molar mass calculations and conversions, resulting in inaccurate grams of CaCO3 needed.

5. In which group of the periodic table are alkali metals located?

• A. Group 1
• B. Group 2
• C. Group 7
• D. Group 8

Correct answer: A

Rationale: Alkali metals, such as lithium, sodium, and potassium, are located in Group 1 of the periodic table. This group is known for its highly reactive properties, low melting points, and the tendency to form alkaline solutions when they react with water. Group 2 consists of alkaline earth metals and not alkali metals, making choice B incorrect. Group 7 includes halogens, while Group 8 includes noble gases. These groups do not contain alkali metals, so choices C and D are also incorrect. Therefore, the correct answer is Group 1.

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