Nursing Elites

1. DNA has both a 'sense' and 'antisense' strand. What is true about the antisense strand?

• A. It runs 5' to 3'.
• B. It runs 3' to 5'.
• C. It is used in replication.
• D. It is the direction DNA is stored.

Correct answer: B

Rationale: The correct answer is B: 'It runs 3' to 5'. The antisense strand runs in the 3' to 5' direction, complementing the sense strand. Choice A is incorrect as the antisense strand runs in the opposite direction, which is 3' to 5'. Choice C is incorrect because the antisense strand is not directly involved in replication. Choice D is incorrect as the direction DNA is stored is not determined by the antisense strand.

2. Which of the following distinguishes the isotopes of an element?

• A. Isotopes are atoms of the same element that have different ionic charges.
• B. Isotopes are atoms of elements within the same group on the periodic table.
• C. Isotopes are atoms of the same element that have different numbers of neutrons.
• D. Isotopes are atoms of the same element with different electron configurations.

Correct answer: C

Rationale: Isotopes are defined as atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons. This leads to variations in atomic mass for isotopes of an element. The different number of neutrons in isotopes results in differences in their atomic mass and properties while still belonging to the same element. Choice A is incorrect because isotopes do not have different ionic charges, they have the same chemical properties. Choice B is incorrect because isotopes are not atoms of elements within the same group on the periodic table; they are variants of the same element. Choice D is incorrect because isotopes of an element have the same electron configuration, differing only in the number of neutrons in the nucleus.

3. What is the breakdown product of creatine phosphate, an energy source used for short bursts of muscle activity?

• A. Glucose
• B. Lactic acid
• C. Carbon dioxide
• D. Creatine

Correct answer: B

Rationale: Creatine phosphate is utilized as an immediate energy source for short bursts of muscle activity. When it breaks down, it yields lactic acid as a byproduct. Lactic acid accumulation during intense exercise can lead to muscle fatigue and soreness. Therefore, the correct answer is lactic acid. The other choices are incorrect: Glucose is a different energy source derived from carbohydrates; Carbon dioxide is a waste product of cellular respiration, not specifically from creatine phosphate breakdown; Creatine is the precursor compound to creatine phosphate and is not the breakdown product.

4. During inhalation, which muscle contracts to increase the volume of the thoracic cavity, allowing air to flow into the lungs?

• A. Diaphragm
• B. Intercostal muscles
• C. Abdominal muscles
• D. Pectoral muscles

Correct answer: A

Rationale: The diaphragm is the primary muscle responsible for inhalation. When it contracts, it moves downward, increasing the volume of the thoracic cavity and creating a pressure gradient that allows air to flow into the lungs. While the intercostal muscles also play a role in expanding the chest cavity during inhalation, the diaphragm is the main muscle involved in this process. Abdominal muscles and pectoral muscles are not directly involved in the process of inhalation.

5. What property of a substance measures the amount of matter per unit volume?

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

Correct answer: C

Rationale: Density is the property of a substance that measures the amount of matter per unit volume. It is calculated by dividing the mass of an object by its volume. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. Therefore, in this context, density is the correct answer as it specifically relates to the concentration of matter within a given volume.

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