Nursing Elites

1. Which of the following describes how atomic radius varies across the periodic table?

• A. Atomic radius increases from top to bottom and left to right on the periodic table.
• B. Atomic radius increases from top to bottom and right to left on the periodic table.
• C. Atomic radius increases from top to bottom and toward the halogens on the periodic table.
• D. Atomic radius increases from top to bottom and toward the noble gases on the periodic table.

Correct answer: A

Rationale: Atomic radius tends to increase from top to bottom and left to right on the periodic table. This is because as you move down a group (top to bottom), new energy levels are added, increasing the distance of the outer electrons from the nucleus and thus increasing the size of the atom. On the other hand, as you move from left to right across a period, the number of protons and electrons increases, leading to a stronger nuclear charge that attracts the electrons closer to the nucleus, resulting in smaller atomic radii. Choice B is incorrect as atomic radius does not increase from right to left. Choices C and D are incorrect as they incorrectly associate the trend with specific groups of elements (halogens and noble gases) rather than the general trend observed on the periodic table.

2. Which concentration unit depends on pressure?

• A. ppm
• B. ppb
• C. molarity
• D. molarity, ppb, and ppm

Correct answer: C

Rationale: The correct answer is 'C: molarity.' Molarity is the concentration unit that depends on pressure. In molarity, the concentration of a solution is expressed as the number of moles of solute per liter of solution. This means that changes in pressure can affect the volume of the solution and consequently the concentration. Choices A and B, ppm (parts per million) and ppb (parts per billion), respectively, are independent of pressure variations as they are based on mass ratios. Therefore, molarity is the only concentration unit listed that is directly influenced by changes in pressure.

3. Which plane divides the body into superior (top) and inferior (bottom) halves?

• A. Sagittal/Median Plane
• B. Frontal/Coronal Plane
• C. Transverse/Cross-Section Plane
• D. Horizontal Plane

Correct answer: C

Rationale: The Transverse or Cross-Section Plane is the correct answer as it divides the body into superior (top) and inferior (bottom) halves. This plane runs horizontally across the body, perpendicular to the long axis, separating the body into upper and lower sections. Choice A, the Sagittal/Median Plane, divides the body into left and right halves, not superior and inferior halves. Choice B, the Frontal/Coronal Plane, divides the body into anterior (front) and posterior (back) halves. Choice D, the Horizontal Plane, is not a standard anatomical plane used to divide the body into specific sections.

4. Which of the following correctly identifies a difference between the primary and secondary immune response?

• A. In the secondary response, macrophages migrate to the lymph nodes to present the foreign microorganism to helper T lymphocytes.
• B. The humoral immunity that characterizes the primary response is coordinated by B lymphocytes.
• C. The primary response is quicker and more powerful than the secondary response.
• D. Suppressor T cells are activated in the secondary response to prevent an overactive immune response.

Correct answer: C

Rationale: The correct answer is C. The primary immune response is slower and less powerful compared to the secondary immune response. During the primary response, immune cells encounter the antigen for the first time, necessitating the activation and proliferation of specific immune cells. In contrast, the secondary response benefits from memory cells that quickly recognize the antigen, enabling a faster and more potent immune response. Choices A, B, and D are incorrect. While macrophages play a role in presenting antigens to T cells, this is not a defining difference between primary and secondary responses. Humoral immunity involves B lymphocytes in both primary and secondary responses, so it does not differentiate the two. Suppressor T cells primarily function to regulate the immune response but are not a key factor distinguishing primary from secondary responses.

5. How can a single gene mutation lead to multiple phenotypes depending on the organism?

• A. Pleiotropy describes the effect of one gene influencing multiple seemingly unrelated traits.
• B. Epigenetics involves environmental factors modifying gene expression without altering the DNA sequence.
• C. Genetic drift refers to random changes in allele frequencies within a population.
• D. Gene regulation controls the timing and level of gene expression within an organism.

Correct answer: A

Rationale: A single gene mutation can lead to multiple phenotypes through pleiotropy, where one gene influences diverse traits or functions in an organism. This phenomenon occurs when the mutated gene affects different biochemical pathways, developmental processes, or cellular functions, resulting in a cascade of downstream effects that manifest as a variety of phenotypic outcomes. Choice B, epigenetics, involves modifications in gene expression influenced by environmental factors without altering the DNA sequence, which is not directly related to the question about single gene mutations causing multiple phenotypes. Choice C, genetic drift, refers to random changes in allele frequencies within a population, which is unrelated to the impact of a single gene mutation on multiple phenotypes. Choice D, gene regulation, focuses on controlling the timing and level of gene expression within an organism, which is not directly addressing how a single gene mutation can lead to diverse phenotypes.

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