Nursing Elites

1. Which enzyme plays a crucial role in DNA replication during the S phase of interphase?

• A. Helicase
• B. DNA polymerase
• C. Ligase
• D. Topoisomerase

Correct answer: B

Rationale: During the S phase of interphase, DNA replication takes place. DNA polymerase is the enzyme responsible for synthesizing new DNA strands by adding nucleotides in a complementary manner to the template strand. It plays a pivotal role in accurately replicating the entire genome. While helicase unwinds the double-stranded DNA for replication, topoisomerase relieves the tension in the DNA strands, and ligase joins the Okazaki fragments on the lagging strand. However, DNA polymerase directly participates in the synthesis of new DNA strands during replication, making it the correct answer.

2. The process by which a single-celled organism divides into two identical daughter cells is called

• A. Conjugation
• B. Binary fission
• C. Endocytosis
• D. Mitosis

Correct answer: B

Rationale: Rationale: A) Conjugation is a process in which genetic material is transferred between two bacterial cells through a conjugation tube. It does not involve the division of a single-celled organism into two identical daughter cells. B) Binary fission is the process by which a single-celled organism, such as a bacterium, divides into two identical daughter cells. This is a common method of reproduction in prokaryotic organisms. C) Endocytosis is a cellular process in which cells engulf external materials by wrapping them in a vesicle. It is not a method of cell division. D) Mitosis is a type of cell division that occurs in eukaryotic cells, leading to the production of two daughter cells with identical genetic material. However, the question specifically refers to a single-celled organism, which typically undergoes binary fission for reproduction.

3. Which of the following is NOT an example of a homeostatic mechanism?

• A. Shivering when the body temperature falls.
• B. Increasing heart rate when blood pressure is low.
• C. Weight gain when consuming excess calories.
• D. Secreting insulin to decrease blood sugar concentration.

Correct answer: C

Rationale: Weight gain when consuming excess calories is not an example of a homeostatic mechanism. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. The other options listed (A, B, and D) involve physiological responses aimed at restoring balance or stability within the body (e.g., regulating body temperature, blood pressure, and blood sugar levels). Shivering, increasing heart rate, and secreting insulin are mechanisms to counteract specific imbalances and maintain internal equilibrium. In contrast, weight gain due to excess calorie intake does not represent a specific regulatory mechanism but rather an outcome of energy imbalance. The body stores excess energy as fat rather than actively regulating a physiological parameter to restore balance.

4. Following successful heart transplant surgery, the patient's body will need to take medications to:

• A. Suppress the immune system and prevent rejection of the new heart.
• B. Reduce overall blood pressure.
• C. Dissolve any remaining blood clots.
• D. Stimulate the growth of new heart tissue.

Correct answer: A

Rationale: After heart transplant surgery, the patient's body will need to take medications to suppress the immune system and prevent rejection of the new heart. This is essential to ensure that the body does not identify the transplanted heart as a foreign entity and mount an immune response against it, which could lead to transplant rejection and failure. Choices B, C, and D are incorrect because post-heart transplant medications primarily focus on preventing rejection by suppressing the immune system, rather than reducing blood pressure, dissolving blood clots, or stimulating the growth of new heart tissue.

5. Which property of a substance refers to its ability to be stretched into thin wires without breaking?

• A. Conductivity
• B. Viscosity
• C. Ductility
• D. Malleability

Correct answer: C

Rationale: Ductility is the property of a substance that allows it to be stretched into thin wires without breaking. This property is distinct from the other options provided. Conductivity refers to the ability to conduct electricity or heat, viscosity refers to a liquid's resistance to flow, and malleability refers to the ability of a substance to be hammered or rolled into thin sheets. Therefore, the correct answer is 'Ductility.'

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