Nursing Elites

1. 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.

2. Which type of wave requires a medium to travel through?

• A. Electromagnetic waves
• B. Mechanical waves
• C. Sound waves
• D. Both A and C

Correct answer: B

Rationale: Mechanical waves, unlike electromagnetic waves, require a medium (such as air, water, or solids) to propagate. Sound waves are a specific type of mechanical wave that necessitates a medium, like air or water, for transmission. Electromagnetic waves, on the other hand, can travel through a vacuum as they do not rely on a medium for propagation. Choice A (Electromagnetic waves) is incorrect since they do not require a medium to travel. Choice C (Sound waves) is partially correct in that it is a type of mechanical wave that needs a medium but is not the only type. Choice D (Both A and C) is incorrect because electromagnetic waves do not require a medium, only mechanical waves like sound waves do.

3. Centrioles are structures involved in cell division. What is their specific role?

• A. Forming the nuclear envelope
• B. Replicating DNA
• C. Organizing microtubules during cell division
• D. Protein synthesis

Correct answer: C

Rationale: Centrioles are involved in organizing microtubules during cell division, specifically in forming the mitotic spindle. The mitotic spindle is crucial for the proper alignment and separation of chromosomes during cell division, ensuring the accurate distribution of genetic material to daughter cells. Choice A, forming the nuclear envelope, is incorrect as centrioles do not have a direct role in this process. Choice B, replicating DNA, is incorrect as centrioles are not involved in DNA replication. Choice D, protein synthesis, is incorrect as centrioles do not play a role in protein synthesis.

4. Which structure connects the two hemispheres of the brain, allowing communication and coordination between them?

• A. Corpus callosum
• B. Thalamus
• C. Hypothalamus
• D. Medulla oblongata

Correct answer: A

Rationale: The correct answer is the corpus callosum. It is a thick band of nerve fibers that connects the two hemispheres of the brain, facilitating communication and coordination between them. The thalamus acts as a relay station for sensory information, the hypothalamus regulates basic functions like hunger and thirst, and the medulla oblongata controls vital functions such as breathing and heart rate. Therefore, choices B, C, and D are incorrect as they do not specifically connect the two hemispheres of the brain as the corpus callosum does.

5. Which nitrogenous bases pair with each other in DNA?

• A. A-G and T-C
• B. A-T and C-G
• C. A-T and T-T
• D. C-C and G-G

Correct answer: B

Rationale: In DNA, nitrogenous bases pair with each other in a specific manner known as complementary base pairing. Adenine (A) always pairs with Thymine (T), and Cytosine (C) always pairs with Guanine (G). This pairing is essential for maintaining the structure and function of DNA. Option B is the correct answer as it correctly identifies the nitrogenous bases that pair with each other in DNA. Choices A, C, and D are incorrect because they do not follow the established base pairing rules in DNA. A-T and C-G are the complementary base pairs in DNA, ensuring the stability and replication fidelity of the genetic material.

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