Nursing Elites

1. Which level of protein structure is defined by the folds and coils of the protein's polypeptide backbone?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Quaternary

Correct answer: B

Rationale: The correct answer is B: Secondary. The secondary structure of a protein is defined by the folds and coils of the protein's polypeptide backbone. This level of structure is characterized by the formation of alpha helices and beta sheets, which are stabilized by hydrogen bonds between amino acids along the polypeptide chain. Choice A, Primary, refers to the linear sequence of amino acids in the protein. Choice C, Tertiary, involves the 3D folding of the entire polypeptide chain. Choice D, Quaternary, pertains to the arrangement of multiple polypeptide subunits in a protein complex.

2. What type of force enables a car to take a sharp turn while moving in a circular path?

• A. Centripetal force
• B. Tension force
• C. Frictional force
• D. Gravitational force

Correct answer: A

Rationale: Centripetal force is the force that allows an object to move in a circular path. When a car takes a sharp turn, centripetal force acts towards the center of the circle, enabling the car to stay in the curved path. Tension force is transmitted through a string, rope, cable, or wire when pulled tight, and it is not directly related to a car's turning motion. Frictional force opposes motion and is not the primary force responsible for a car's ability to take a sharp turn. Gravitational force is the attraction between masses and does not directly influence a car's ability to maneuver in a curved path.

3. Which type of wave requires a medium to travel through?

• A. Electromagnetic waves
• B. Mechanical waves
• C. Sound waves
• D. Both A and C

Correct answer: B

Rationale: Mechanical waves, unlike electromagnetic waves, require a medium (such as air, water, or solids) to propagate. Sound waves are a specific type of mechanical wave that necessitates a medium, like air or water, for transmission. Electromagnetic waves, on the other hand, can travel through a vacuum as they do not rely on a medium for propagation. Choice A (Electromagnetic waves) is incorrect since they do not require a medium to travel. Choice C (Sound waves) is partially correct in that it is a type of mechanical wave that needs a medium but is not the only type. Choice D (Both A and C) is incorrect because electromagnetic waves do not require a medium, only mechanical waves like sound waves do.

4. How many kilograms are in 1,800 grams?

• A. 0.18
• B. 1.8
• C. 18
• D. 180

Correct answer: B

Rationale: To convert grams to kilograms, divide by 1,000 since there are 1,000 grams in a kilogram. Therefore, 1,800 grams is equal to 1.8 kilograms (1,800 / 1,000 = 1.8). Choice A (0.18) is incorrect because it incorrectly shifted the decimal point. Choice C (18) is incorrect as it represents the direct conversion without dividing by 1,000. Choice D (180) is incorrect as it is in the hundreds and not the correct conversion to kilograms. The correct answer is B.

5. How many moles of oxygen are required to completely react with 5 moles of propane (C3H8) in the combustion reaction?

• A. 5 moles
• B. 10 moles
• C. 15 moles
• D. 20 moles

Correct answer: C

Rationale: In the balanced chemical equation for the combustion of propane (C3H8): C3H8 + 5O2 → 3CO2 + 4H2O, 1 mole of propane (C3H8) reacts with 5 moles of oxygen (O2). To determine the moles of oxygen required to react with 5 moles of propane, we use the molar ratio: 5 moles propane x 5 moles oxygen / 1 mole propane = 25 moles oxygen. However, since the question specifically asks for the moles of oxygen needed to react with 5 moles of propane, the correct answer is 15 moles of oxygen. Choice A, 5 moles, is incorrect because this is the amount of propane provided, not the oxygen required. Choice B, 10 moles, is incorrect as it does not correspond to the molar ratio in the balanced equation. Choice D, 20 moles, is incorrect as it is not in line with the stoichiometry of the reaction.

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