Nursing Elites

1. A ball is thrown upwards. Which of the following statements is TRUE about its potential energy and kinetic energy at the peak of its trajectory?

• A. Both potential and kinetic energy are zero.
• B. Potential energy is maximum and kinetic energy is minimum.
• C. Potential energy is minimum and kinetic energy is maximum.
• D. Both potential and kinetic energy remain constant.

Correct answer: B

Rationale: At the peak of its trajectory, the ball momentarily stops moving before falling back down. This means its kinetic energy is at a minimum because it has come to a stop. At the same time, its potential energy is at a maximum because it is at the highest point in its trajectory, where it has the most potential to fall and convert that potential energy into kinetic energy as it descends. Choice A is incorrect because at the peak, the ball still has potential energy due to its height. Choice C is incorrect because kinetic energy is at a minimum when the ball is momentarily at rest. Choice D is incorrect because the energy conversion between potential and kinetic energy occurs at different points in the trajectory.

2. Which of the following vessels is responsible for transporting blood from the heart to the lungs?

• A. Pulmonary vein
• B. Pulmonary artery
• C. Aorta
• D. Superior vena cava

Correct answer: B

Rationale: The correct answer is B, Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart's right ventricle to the lungs for oxygenation. This blood then undergoes the gas exchange process in the lungs, where carbon dioxide is removed, and oxygen is absorbed. The pulmonary vein, identified in choice A, carries oxygenated blood from the lungs back to the heart, which is the opposite direction of the blood flow specified in the question. Choice C, Aorta, is responsible for carrying oxygen-rich blood from the heart's left ventricle to the rest of the body, not to the lungs. Choice D, Superior vena cava, returns deoxygenated blood from the upper body to the heart's right atrium, but it does not transport blood specifically to the lungs as requested in the question.

3. Which valve prevents the return of blood into the right ventricle?

• A. Pulmonary semilunar valve
• B. Aortic semilunar valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: A

Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.

4. What is the role of enzymes in the body?

• A. To transport oxygen
• B. To speed up chemical reactions
• C. To regulate body temperature
• D. To store energy

Correct answer: B

Rationale: Enzymes act as biological catalysts that speed up chemical reactions in the body. They lower the activation energy required for reactions to occur, thus facilitating processes like digestion, metabolism, and other essential functions. Choice A is incorrect as the transportation of oxygen is primarily carried out by red blood cells. Choice C is incorrect as the regulation of body temperature involves mechanisms such as sweating and shivering. Choice D is incorrect as energy storage is mainly performed by molecules like glycogen and triglycerides.

5. What is the main component of sweat?

• A. Urea
• B. Glucose
• C. Water
• D. Electrolytes

Correct answer: C

Rationale: - Sweat is primarily composed of water, making up the majority of its content. Water helps regulate body temperature by evaporating from the skin's surface, which cools the body down. - While sweat does contain small amounts of other substances like urea, glucose, and electrolytes, water is the main component that is secreted by sweat glands to help regulate body temperature during physical activity or in response to heat.

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