Nursing Elites

1. Examine the following decomposition reaction: ABC → ______. Which of the following is a possible set of products for this reaction?

• A. 2AB + C
• B. AB + CD
• C. A + BC
• D. B + C

Correct answer: C

Rationale: In a decomposition reaction, a single reactant breaks down into two or more products. For the decomposition of ABC, a plausible set of products is A + BC. This reaction represents the breakdown of ABC into two separate components: A and BC. The correct choice C aligns with the fundamental concept of decomposition reactions, where a compound disintegrates into simpler substances. Choices A, B, and D do not reflect a proper decomposition reaction as they do not demonstrate the breakdown of the original compound into distinct components.

2. Which of the following nutrients is correctly matched with its foundational components?

• A. Carbohydrates are formed when glucose molecules bond together.
• B. Lipids consist of fatty acids and glycerol.
• C. Nucleic acids consist of nitrogenous bases, sugar, and phosphate groups.
• D. Proteins consist of strings of amino acids.

Correct answer: D

Rationale: Proteins consist of strings of amino acids. Amino acids are the basic building blocks of proteins, and they are linked together in a specific sequence to form a protein structure. This is a correct match between the nutrient (proteins) and its foundational components (amino acids). Choices A, B, and C are incorrect as they do not accurately match the foundational components of the respective nutrients. Carbohydrates are not formed by glucose molecules bonding together; they are made up of sugar molecules. Lipids consist of fatty acids and glycerol, but they are not nutrients typically associated with bonding for formation. Nucleic acids do consist of nitrogenous bases, sugar, and phosphate groups, but they are not the correct match for the question.

3. Which of the following does not describe a general trait of macromolecules?

• A. They can exist as single chains.
• B. They can be branched.
• C. They all contain carbon, hydrogen, and phosphorus.
• D. They are all used by the body.

Correct answer: C

Rationale: The correct answer is C. While many macromolecules contain carbon, hydrogen, and phosphorus, not all of them do. For example, lipids, a type of macromolecule, may not contain phosphorus. Choice A and B describe structural features that macromolecules can exhibit, whether as single chains or branched forms. Choice D is incorrect as not all macromolecules are used by the body, such as synthetic polymers or certain non-digestible fibers.

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. Elements tend to gain or lose electrons to achieve stable electron configurations like those of noble gases. Their group number often indicates the number of electrons gained/lost and the resulting ionic charge, providing a good starting point for prediction.

• A. Ionic bonds involve electron sharing, while metallic bonds involve electron transfer.
• B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
• C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
• D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: C

Rationale: Ionic bonds typically form between metals and non-metals, where one atom donates electrons (cation) and the other accepts electrons (anion). This results in the transfer of electrons. Metallic bonds, on the other hand, occur between metal atoms where electrons are shared among a sea of delocalized electrons, leading to the characteristic properties of metals like malleability and conductivity. Choice A is incorrect because ionic bonds involve electron transfer, not sharing. Choice B is incorrect as ionic bonds are strong, not weak, and are non-directional, while metallic bonds are strong and non-directional. Choice D is incorrect as ionic bonds do not form discrete molecules but rather a lattice structure, whereas metallic bonds form extended structures.

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