Nursing Elites

1. Which of the following enzymes is responsible for adding a nucleotide to a growing DNA chain?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: D

Rationale: The correct answer is Polymerase. Polymerase is the enzyme responsible for adding nucleotides to a growing DNA chain during DNA replication. Helicase unwinds the DNA double helix to separate the DNA strands for replication, Ligase joins DNA fragments together by catalyzing the formation of phosphodiester bonds between them, and Nuclease cuts or degrades DNA strands. Therefore, choices A, B, and C are incorrect in the context of adding nucleotides to a growing DNA chain.

2. What property of a substance remains constant regardless of changes in its location in the universe?

• A. Mass
• B. Weight
• C. Density
• D. Volume

Correct answer: A

Rationale: Mass is the amount of matter in an object and remains constant regardless of its location in the universe. Weight, on the other hand, is the force of gravity acting on an object and can vary depending on the gravitational pull at different locations. Density and volume can change based on the conditions the substance is in, so they are not constant properties. Therefore, the correct answer is mass as it does not change with changes in location.

3. How does meiosis differ from mitosis?

• A. Meiosis is used for repairing the body. Mitosis is used for cell reproduction.
• B. Meiosis is used for sexual reproduction. Mitosis is used for asexual reproduction.
• C. Meiosis occurs in various organisms. Mitosis occurs in various organisms.
• D. Meiosis produces cells that are genetically different. Mitosis produces cells that are genetically identical.

Correct answer: D

Rationale: Meiosis is the process of cell division that results in the formation of sex cells (gametes) with only half the number of chromosomes as the parent cell, leading to genetically different cells. In contrast, mitosis is a cell division process that produces two daughter cells that are genetically identical to each other and the parent cell, maintaining the same chromosome number. Therefore, the correct answer is D, as meiosis and mitosis differ in their genetic outcomes - meiosis results in genetic diversity, while mitosis maintains genetic identity. Choices A, B, and C are incorrect because they do not accurately distinguish between meiosis and mitosis. Meiosis is not used for repairing the body or asexual reproduction, and the occurrence of both processes in various organisms does not highlight their primary differences in genetic outcomes.

4. Which part of the heart is responsible for generating the QRS complex on an ECG?

• A. Sinoatrial node (SA node)
• B. Atrioventricular node (AV node)
• C. Bundle of His
• D. Ventricular muscle cells

Correct answer: D

Rationale: The QRS complex on an ECG represents ventricular depolarization. This electrical activity is generated by the ventricular muscle cells. While the SA node generates the P wave, the AV node delays the impulse, and the Bundle of His and Purkinje fibers assist in rapidly conducting the impulse through the ventricles, it is the ventricular muscle cells that specifically create the QRS complex. Therefore, choice D, Ventricular muscle cells, is the correct answer. Choices A, B, and C are incorrect as they are primarily involved in initiating and coordinating the electrical impulses in the heart but do not directly generate the QRS complex on an ECG.

5. Which hormone, produced by the pancreas, regulates blood sugar levels by promoting the uptake of glucose into cells?

• A. Insulin
• B. Glucagon
• C. Cortisol
• D. Thyroxine

Correct answer: A

Rationale: Insulin is the correct answer. It is produced by the pancreas and plays a crucial role in regulating blood sugar levels by facilitating the absorption of glucose into cells. When blood sugar levels are elevated, insulin is released to help cells utilize glucose for energy or store it for future use. Glucagon, choice B, is produced by the pancreas as well but has the opposite effect of raising blood sugar levels by releasing stored glucose into the bloodstream. Cortisol, choice C, is a hormone produced by the adrenal glands that is involved in the stress response and metabolism, not specifically in regulating blood sugar levels. Thyroxine, choice D, is a hormone produced by the thyroid gland that regulates metabolism but is not directly involved in the uptake of glucose into cells.

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