Nursing Elites

1. Which of the following statements best defines an organelle?

• A. Layer of polysaccharides outside the plasma membrane of cells.
• B. Abnormal infectious proteins.
• C. Specialized structures within a cell.
• D. Collection of tissues used to serve a specific function.

Correct answer: C

Rationale: The correct answer is C: 'Specialized structures within a cell.' An organelle is a specialized subunit within a cell that has a specific function. Organelles are membrane-bound structures found within the cytoplasm of eukaryotic cells, each performing distinct roles that contribute to the overall functioning of the cell. Choices A, B, and D are incorrect. Option A describes the glycocalyx, which is a layer of polysaccharides outside the plasma membrane of cells. Option B refers to prions, abnormal infectious proteins. Option D defines an organ, a collection of tissues used to serve a specific function, rather than an organelle within a cell.

2. A light ray travels from air (refractive index 1.00) into water (refractive index 1.33). What happens to its speed and direction?

• A. Speed increases, direction bends towards the normal.
• B. Speed increases, direction bends away from the normal.
• C. Speed decreases, direction bends towards the normal.
• D. Speed and direction remain unchanged.

Correct answer: C

Rationale: When a light ray travels from air (lower refractive index) to water (higher refractive index), its speed decreases due to the change in the medium. This is because light travels slower in denser mediums. As the light ray enters the denser medium, water in this case, it bends towards the normal (the line perpendicular to the surface of the water). This phenomenon is known as refraction. Choice A is incorrect as the speed of light decreases when entering a denser medium. Choice B is incorrect as the direction bends towards the normal, not away from it. Choice D is incorrect as the speed and direction of the light ray do change when moving from air to water.

3. Which of the following substances is NOT a product of cellular respiration?

• A. Carbon dioxide
• B. Water
• C. Oxygen
• D. ATP

Correct answer: C

Rationale: The correct answer is C. Oxygen is not a product of cellular respiration; instead, it is consumed during the process. During cellular respiration, glucose is broken down in the presence of oxygen to produce energy in the form of ATP, carbon dioxide, and water. Carbon dioxide is released as a waste product, water is a byproduct of the chemical reactions, and ATP is the energy currency used by cells. Therefore, options A, B, and D are all products or outcomes of cellular respiration, while oxygen is a reactant.

4. Which structure in the respiratory system is responsible for gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchi
• D. Diaphragm

Correct answer: B

Rationale: The alveoli in the lungs are responsible for gas exchange. Alveoli have a rich blood supply and thin walls, enabling the exchange of oxygen and carbon dioxide. Oxygen diffuses into the blood from the alveoli, while carbon dioxide diffuses out. The trachea functions as an air passage, bronchi are the main airways into the lungs, and the diaphragm is the primary muscle involved in breathing by aiding in lung expansion and contraction, but they are not directly responsible for gas exchange like the alveoli.

5. Which part of the brain is responsible for regulating body temperature, hunger, and thirst, and is considered a key player in the endocrine system?

• A. Amygdala
• B. Hippocampus
• C. Hypothalamus
• D. Thalamus

Correct answer: C

Rationale: The hypothalamus is responsible for regulating body temperature, hunger, and thirst, making it a vital component in maintaining homeostasis. It also plays a crucial role in the endocrine system by controlling the release of hormones from the pituitary gland. The amygdala primarily processes emotions, the hippocampus is associated with memory formation, and the thalamus acts as a relay station for sensory information. Therefore, the hypothalamus is the correct answer as it directly regulates the physiological processes mentioned in the question.

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