Nursing Elites

1. When ice melts, it undergoes a…

• A. Chemical change
• B. Physical change
• C. Nuclear change
• D. Radioactive decay

Correct answer: B

Rationale: Melting is a change in physical state, not a change in the chemical composition of the ice.

2. Explain how a single gene mutation can 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 affect different biochemical pathways or developmental processes, leading to a cascade of downstream effects and diverse phenotypic consequences.

3. What is the product of the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH)?

• A. NaCl + H2O
• B. NaOH + HCl
• C. Na2Cl + H2O
• D. NaClO3 + H2

Correct answer: a

Rationale: The reaction between HCl and NaOH results in the formation of sodium chloride (NaCl) and water (H2O).

4. Cartilage is a flexible connective tissue found in the:

• A. Center of long bones
• B. Joints between bones
• C. Muscle tissue
• D. Walls of blood vessels

Correct answer: A

Rationale: Cartilage is a flexible connective tissue that is found in the joints between bones. It is a strong yet flexible tissue that cushions and supports the joints, allowing for smooth movement and reducing friction between bones. Cartilage is not typically found in the center of long bones, muscle tissue, or walls of blood vessels. Therefore, the correct answer is B: 'Joints between bones.'

5. T cells in the immune system can be categorized into different types. What type of T cell directly kills infected body cells?

• A. Helper T cells
• B. Cytotoxic T cells
• C. Regulatory T cells
• D. Memory T cells

Correct answer: B

Rationale: Cytotoxic T cells directly kill infected body cells. These T cells recognize and destroy cells that are infected with viruses or other pathogens. They are crucial for eliminating threats within the body. Helper T cells, on the other hand, assist in coordinating the immune response by activating other immune cells. Regulatory T cells help maintain immune tolerance and prevent autoimmune reactions. Memory T cells are responsible for 'remembering' specific pathogens to mount a faster and stronger immune response upon re-exposure. Therefore, cytotoxic T cells are the correct answer as they directly target and kill infected cells.

6. Which of the following is an example of a commensal relationship between a microorganism and a human?

• A. Salmonella causing food poisoning
• B. taphylococcus aureus causing skin infections
• C. coli living in the gut
• D. Rabies virus causing neurological disease

Correct answer: C

Rationale: Rationale: A commensal relationship is a type of symbiotic relationship in which one organism benefits, while the other is neither harmed nor benefited. In this case, E. coli living in the gut is an example of a commensal relationship because it can benefit from the environment in the gut without causing harm to the human host. Option A, Salmonella causing food poisoning, is an example of a pathogenic relationship where the microorganism causes harm to the host. Option B, Staphylococcus aureus causing skin infections, is also an example of a pathogenic relationship where the microorganism causes harm to the host. Option D, Rabies virus causing neurological disease, is another example of a pathogenic relationship where the microorganism causes harm to the host.

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