Nursing Elites

1. What phenomenon occurs when a wave encounters a change in medium causing a change in its speed and direction?

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Interference

Correct answer: a

Rationale: Refraction happens when a wave changes its speed and direction due to encountering a change in medium.

2. The hormone responsible for regulating blood sugar levels is produced by the:

• A. Pituitary gland
• B. Thyroid gland
• C. Pancreas
• D. Adrenal glands

Correct answer: C

Rationale: The correct answer is C: Pancreas. The hormone responsible for regulating blood sugar levels is insulin, which is produced by the pancreas. Insulin helps to lower blood sugar levels by allowing cells to take in glucose from the bloodstream. The pituitary gland (A) is known for producing various hormones that regulate other endocrine glands, while the thyroid gland (B) produces hormones that regulate metabolism. The adrenal glands (D) produce hormones such as cortisol and adrenaline, but they are not primarily responsible for regulating blood sugar levels.

3. Nutrients are absorbed into the bloodstream through which part of the digestive system?

• A. Stomach
• B. Large intestine
• C. Small intestine
• D. Esophagus

Correct answer: C

Rationale: The correct answer is C: Small intestine. The small intestine is where most of the absorption of nutrients takes place in the digestive system. Its inner lining is covered with tiny finger-like projections called villi, which increase the surface area for absorption. Nutrients such as carbohydrates, proteins, fats, vitamins, and minerals are absorbed into the bloodstream through the walls of the small intestine. The stomach primarily helps with the initial digestion of food, the large intestine absorbs water and salts, and the esophagus is the tube that carries food from the mouth to the stomach. Therefore, the small intestine is the main site of nutrient absorption in the digestive system.

4. Which of the following is NOT a part of a plant cell?

• A. Cell wall
• B. Plasma membrane
• C. Vacuole
• D. Mitochondria

Correct answer: D

Rationale: Rationale: A) Cell wall: This is a structure found in plant cells that provides support and protection. B) Plasma membrane: Also known as the cell membrane, it surrounds the cell and regulates the passage of substances in and out of the cell. C) Vacuole: This is a storage organelle found in plant cells that stores water, nutrients, and waste products. D) Mitochondria: Mitochondria are membrane-bound organelles found in both plant and animal cells. They are responsible for producing energy in the form of ATP through cellular respiration. Therefore, the correct answer is D) Mitochondria, as it is a part of a plant cell.

5. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?

• A. To initiate nerve impulses
• B. To transmit sensory information
• C. To speed up the transmission of nerve impulses
• D. To connect neurons at synapses

Correct answer: c

Rationale: The primary function of the myelin sheath that surrounds some axons in the nervous system is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer, which helps nerve impulses travel faster along the axon by allowing them to 'jump' from one node of Ranvier to the next, a process known as saltatory conduction. This increases the efficiency and speed of signal transmission, enabling rapid communication within the nervous system. Therefore, option C is the correct answer as it accurately describes the role of the myelin sheath in enhancing the speed of nerve impulse transmission.

6. What is the "lock-and-key" model?

• A. Protein folding
• B. Enzyme-substrate interaction
• C. Muscle contraction
• D. Blood clotting

Correct answer: B

Rationale: Rationale: The "lock-and-key" model is a concept used to describe the specificity of the interaction between enzymes and their substrates. In this model, the enzyme's active site is like a lock that can only be opened by the specific substrate molecule, which acts as the key. This specific binding ensures that enzymes catalyze specific reactions and do not interact with other molecules indiscriminately. Protein folding (option A) refers to the process by which a protein adopts its functional three-dimensional structure, but it is not specifically related to the lock-and-key model. Muscle contraction (option C) and blood clotting (option D) are biological processes that involve complex mechanisms but are not directly related to the lock-and-key model of enzyme-substrate interaction.

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