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 of the following is a characteristic of unsaturated fatty acids?

• A. They are solid at room temperature.
• B. They contain only single bonds.
• C. They have a higher melting point.
• D. They contain double or triple bonds.

Correct answer: D

Rationale: The correct answer is D. Unsaturated fatty acids are characterized by the presence of double or triple bonds in their carbon chain. These bonds introduce kinks in the chain, preventing tight packing, and resulting in a lower melting point compared to saturated fatty acids. Choice A is incorrect because unsaturated fatty acids are typically liquid at room temperature due to their kinked structure. Choice B is incorrect because unsaturated fatty acids contain double or triple bonds, not only single bonds. Choice C is incorrect as unsaturated fatty acids have a lower melting point compared to saturated fatty acids.

3. A collection of organs working together to perform a specific physiological function is known as a(n):

• A. Tissue
• B. Organ system
• C. Organelle
• D. Organ

Correct answer: B

Rationale: An organ system is a group of organs that work together to perform specific functions in the body. Each organ within the system has a unique role, but they collaborate to achieve a common physiological function. This collaboration allows the body to carry out complex processes efficiently, demonstrating the interconnectedness and interdependence of different organs within the system. Choice A, 'Tissue,' refers to a group of cells that work together to perform a specific function, not a collection of organs. Choice C, 'Organelle,' is a subunit within a cell that has a specific function and is not a collection of organs. Choice D, 'Organ,' is a single structure composed of different tissues that performs a specific function, not a collection of organs working together.

4. What is the basic unit of heredity?

• A. Chromosome
• B. Cell
• C. Gene
• D. Organ

Correct answer: C

Rationale: A gene is the basic unit of heredity that carries the instructions for making proteins, which determine an organism's traits. Genes are segments of DNA located on chromosomes within the cell. While chromosomes contain many genes, a gene itself is the fundamental unit of heredity responsible for passing on genetic information from one generation to the next. Cells are the basic structural and functional units of living organisms, but genes specifically carry genetic information. Organs are composed of tissues and serve specific functions within an organism, but they are not the basic unit of heredity.

5. Which technology allows scientists to directly edit the human genome?

• A. Polymerase Chain Reaction (PCR)
• B. Gel electrophoresis
• C. DNA sequencing
• D. CRISPR-Cas9

Correct answer: D

Rationale: CRISPR-Cas9 is the correct answer. A) Polymerase Chain Reaction (PCR) is used for amplifying specific DNA segments, not directly editing the human genome. B) Gel electrophoresis is for separating DNA fragments by size, not for genome editing. C) DNA sequencing determines DNA nucleotide order but does not directly edit the genome. D) CRISPR-Cas9 technology enables precise modifications in the DNA of organisms, including humans. It guides the Cas9 enzyme to specific genome locations for targeted edits, revolutionizing genetic research and offering various applications in gene editing and therapy. Unlike the other techniques mentioned, CRISPR-Cas9 is specifically designed to make changes in the genetic code itself, making it a powerful tool for genetic manipulation.

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