Nursing Elites

1. If a biochemist isolates a large amount of pyruvate, which part of the cell is he working with?

• A. Chloroplasts
• B. Cytoplasm
• C. Mitochondria
• D. Nucleus

Correct answer: B

Rationale: The correct answer is B: Cytoplasm. Pyruvate is a product of glycolysis, a metabolic pathway that takes place in the cytoplasm of the cell. Therefore, a biochemist isolating a large amount of pyruvate would be working with the cytoplasm of the cell. Choice A, Chloroplasts, is incorrect because pyruvate is not produced in chloroplasts, which are responsible for photosynthesis. Choice C, Mitochondria, is incorrect as pyruvate is produced in the cytoplasm before entering the mitochondria for further metabolism. Choice D, Nucleus, is incorrect as the nucleus is not involved in the production or isolation of pyruvate, which is a metabolic intermediate.

2. 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.

3. Which of the following is an example of a tissue?

• A. chloroplasts
• B. liver
• C. mammal
• D. hamstring

Correct answer: B

Rationale: The correct answer is 'B: liver.' The liver is an example of a tissue. Tissues are groups of cells that work together to perform specific functions in the body. The liver is made up of different types of cells that work together to carry out various essential functions, such as detoxification, metabolism, and storage of nutrients. Option A (chloroplasts) refers to organelles, not tissues. Option D (hamstring) is a muscle, not a tissue. Option C (mammal) represents a higher level of organization than tissues, as it refers to a classification of organisms, not a specific tissue type.

4. Which part of the nervous system is responsible for the “fight-or-flight” response?

• A. Somatic nervous system
• B. Parasympathetic nervous system
• C. Sympathetic nervous system
• D. Enteric nervous system

Correct answer: C

Rationale: The sympathetic nervous system is responsible for the 'fight-or-flight' response, triggering the body's automatic response to a perceived threat or danger. This system initiates physiological changes like increased heart rate, dilated pupils, and the release of adrenaline, preparing the body to confront or escape the threat. The somatic nervous system (Choice A) controls voluntary movements, the parasympathetic nervous system (Choice B) is responsible for the 'rest and digest' response to promote relaxation and digestion, and the enteric nervous system (Choice D) regulates the gastrointestinal system. Therefore, they are not associated with the 'fight-or-flight' response.

5. Which neurotransmitter is responsible for stimulating muscle contraction?

• A. Dopamine
• B. Acetylcholine
• C. Serotonin
• D. Norepinephrine

Correct answer: B

Rationale: Acetylcholine is the neurotransmitter responsible for stimulating muscle contraction at the neuromuscular junction. When an action potential reaches the end of a motor neuron, acetylcholine is released into the synaptic cleft and binds to receptors on the muscle cell membrane, leading to muscle contraction. Dopamine, serotonin, and norepinephrine are neurotransmitters that have different functions in the nervous system and are not directly involved in stimulating muscle contraction. Dopamine is involved in reward and pleasure pathways, serotonin regulates mood and behavior, and norepinephrine is involved in the 'fight or flight' response.

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