Nursing Elites

1. 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.

2. Immunoglobulin G (IgG) is the most abundant antibody type, responsible for:

• A. Immediate allergic reactions
• B. Neutralizing toxins and viruses
• C. Activating other immune cells
• D. Protecting newborns from infections

Correct answer: B

Rationale: Immunoglobulin G (IgG) is indeed the most prevalent antibody type in the blood and tissue fluids. Its primary functions include neutralizing toxins and viruses, promoting phagocytosis, and activating the complement system. IgG plays a crucial role in long-term immunity and provides passive immunity to newborns by crossing the placenta, safeguarding them from infections. Immediate allergic reactions are mainly mediated by IgE, not IgG. While IgM is known for activating other immune cells, IgG focuses on other key functions within the immune response, such as neutralizing pathogens and enhancing phagocytosis. Therefore, the correct answer is B, as IgG is primarily involved in neutralizing toxins and viruses, rather than the other options presented.

3. Through which structure do the kidneys reabsorb water, salts, and nutrients and return them to the body?

• A. Renal artery
• B. Renal vein
• C. Nephron
• D. Glomerulus

Correct answer: C

Rationale: The question has been corrected to specify the structure responsible for reabsorbing water, salts, and nutrients in the kidneys. The correct answer is the nephron, which is the functional unit of the kidney that performs filtration and reabsorption processes. The renal artery brings blood into the kidney for filtration, the renal vein carries filtered blood away from the kidney, and the glomerulus is a part of the nephron where filtration occurs. Therefore, the nephron is the structure that reabsorbs substances and returns them to the body.

4. During antibiotic use, bacteria can evolve resistance. This is an example of:

• A. Coevolution (two species influencing each other's evolution)
• B. Convergent evolution (unrelated organisms evolving similar traits)
• C. Macroevolution (large-scale evolutionary change)
• D. Artificial selection acting on a natural process

Correct answer: D

Rationale: The process of bacteria evolving resistance to antibiotics due to the selective pressure exerted by the antibiotics is an example of artificial selection (human intervention selecting for certain traits) acting on a natural process (bacterial evolution). Antibiotic use creates a selective pressure that favors the survival and reproduction of bacteria with resistance traits, leading to the evolution of antibiotic-resistant strains. - Coevolution (option A) refers to the influence of two species on each other's evolution, which is not the case in the scenario described in the question. - Convergent evolution (option B) involves unrelated organisms evolving similar traits due to similar environmental pressures, which is not directly applicable to the situation of bacteria evolving resistance to antibiotics. - Macroevolution (option C) refers to large-scale evolutionary changes over long periods, which is not specifically demonstrated in the context of bacteria evolving resistance during antibiotic use.

5. What is the first event to occur in a primary immune response?

• A. Macrophages phagocytose pathogens and present their antigens.
• B. Neutrophils aggregate and act as cytotoxic, nonspecific killers of pathogens.
• C. B lymphocytes make pathogen-specific antibodies.
• D. Helper T cells secrete interleukins to activate pathogen-fighting cells.

Correct answer: A

Rationale: The correct answer is A. The initial event in a primary immune response is the phagocytosis of pathogens by macrophages and the subsequent presentation of their antigens, which is crucial for initiating the adaptive immune response. Neutrophils (Choice B) are also involved in the innate immune response, but they typically respond after macrophages. B lymphocytes (Choice C) produce antibodies later in the adaptive immune response, and Helper T cells (Choice D) help in coordinating the immune response but are not the first cells to act in a primary immune response.

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