Nursing Elites

1. What is the small repeating unit in the contractile apparatus of skeletal muscle?

• A. Myofibril
• B. Actin
• C. Sarcomere
• D. Myosin

Correct answer: C

Rationale: The correct answer is 'Sarcomere.' The sarcomere is the smallest repeating unit within myofibrils and is responsible for muscle contraction in skeletal muscle. It consists of overlapping actin and myosin filaments arranged in a highly organized structure that allows for the sliding of filaments during muscle contraction. 'Myofibril' (choice A) is incorrect because it is a larger structure composed of sarcomeres. 'Actin' (choice B) and 'Myosin' (choice D) are incorrect as they are individual proteins that are components of the sarcomere, not the smallest repeating unit itself.

2. Abduction is defined as which of the following?

• A. Movement away from the midline of the body
• B. Movement that results in a decrease in the angle of a joint
• C. Movement that results in an increase in the angle of a joint
• D. Movement towards the midline of the body

Correct answer: A

Rationale: Abduction is defined as movement away from the midline of the body. This movement occurs in the coronal plane and is essential in various body functions such as raising the arms sideways. Choices B, C, and D describe movements that are different from abduction. Choice B refers to flexion, which decreases the angle of a joint. Choice C describes extension, which increases the angle of a joint. Choice D defines adduction, which involves movement towards the midline of the body. Therefore, the correct answer is choice A.

3. Which mineral is crucial for bone strength and is stored in bones and teeth?

• A. Calcium
• B. Iron
• C. Magnesium
• D. Potassium

Correct answer: A

Rationale: Calcium is crucial for bone strength as it is a major mineral stored in bones and teeth. It plays a vital role in maintaining bone density and strength, making it essential for overall bone health. Calcium is essential for various physiological functions, including muscle contraction, nerve transmission, and blood clotting. Inadequate calcium intake can lead to conditions like osteoporosis, where bones become weak and brittle. Iron (Choice B) is important for transporting oxygen in the blood, but it is not stored in bones and does not play a significant role in bone strength. Magnesium (Choice C) is essential for bone health, but it is not primarily stored in bones and teeth. Potassium (Choice D) is crucial for various physiological functions, such as fluid balance and muscle function, but it is not a major mineral stored in bones and teeth for bone strength.

4. Which of the following factors does NOT affect the rate of dissolution of a solute in a solvent?

• A. Temperature
• B. Pressure
• C. Surface area
• D. Particle size

Correct answer: B

Rationale: Pressure does not affect the rate of dissolution of a solute in a solvent. The factors that affect the rate of dissolution include temperature, surface area, and particle size. Temperature generally increases the rate of dissolution by providing more energy for the solute particles to break apart and mix with the solvent. Increasing the surface area of the solute by grinding it into smaller particles or increasing its contact area with the solvent can also speed up dissolution. Similarly, reducing the particle size of the solute can increase the rate of dissolution by providing more surface area for interaction with the solvent. Pressure, however, does not have a significant impact on the dissolution process and is not a factor that influences the rate at which a solute dissolves in a solvent.

5. Which of the following is a property of amphiprotic substances?

• A. React with acids only
• B. React with bases only
• C. Can act as both acids and bases
• D. Are inert in chemical reactions

Correct answer: C

Rationale: The correct answer is C: Can act as both acids and bases. Amphiprotic substances have the ability to donate a proton (act as an acid) or accept a proton (act as a base) depending on the reaction conditions. This dual nature allows them to participate in a wide range of chemical reactions, making them versatile and important in various chemical processes. Choices A and B are incorrect because amphiprotic substances are not limited to reacting with only acids or bases; they can interact with both. Choice D is incorrect because amphiprotic substances are not inert; they actively participate in chemical reactions by donating or accepting protons.

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