Which enzyme functions to break down lactose, a specific sugar found in milk and dairy products?
- A. Catalase
- B. Lipase
- C. Protease
- D. Lactase
Correct Answer: D
Rationale: Lactase is the enzyme responsible for breaking down lactose, a sugar present in milk and dairy products. When lactase breaks down lactose, it splits it into two simpler sugars, glucose, and galactose, which can then be absorbed and used by the body. Catalase is involved in breaking down hydrogen peroxide into water and oxygen. Lipase breaks down fats into fatty acids and glycerol. Protease breaks down proteins into amino acids. Therefore, choices A, B, and C are incorrect for the specific breakdown of lactose.
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Enlargement of the thyroid, commonly known as a goiter, might be expected to affect ___________.
- A. swallowing
- B. insulin levels
- C. sleep
- D. digestion
Correct Answer: A
Rationale: Enlargement of the thyroid, known as a goiter, can compress the nearby structures in the neck, including the esophagus. This compression can lead to symptoms such as difficulty swallowing (dysphagia) or a sensation of pressure in the throat. Therefore, an enlarged thyroid gland is expected to affect swallowing. Choices B, C, and D are incorrect because a goiter primarily affects structures in the neck due to its physical enlargement, rather than directly impacting insulin levels, sleep, or digestion.
How do the muscular and skeletal systems collaborate to facilitate movement?
- A. Muscles attached to tendons contract to bend the skeleton at the joints.
- B. The hard bones of the skeleton protect the voluntary muscles of the limbs.
- C. The cardiac muscles produce calcium that is needed for sturdy bones.
- D. Smooth muscles on internal organs leach excess minerals from the bones.
Correct Answer: A
Rationale: The muscular system and the skeletal system collaborate to facilitate movement. Muscles are connected to bones through tendons and contract to generate movement at the joints. When muscles contract, they exert force on the bones, resulting in actions like bending the arm or leg. This coordinated effort between muscles and bones is crucial for various activities such as walking, running, and grasping objects. Choices B, C, and D are incorrect because they do not accurately describe the interaction between the muscular and skeletal systems. The skeletal system's primary role is to provide structural support and protect internal organs, while cardiac muscles are responsible for heart function and not bone strength. Smooth muscles are found in internal organs and are not involved in leaching excess minerals from bones.
Which structure of the respiratory system is involved in gas exchange?
- A. Trachea
- B. Bronchioles
- C. Alveoli
- D. Larynx
Correct Answer: C
Rationale: The alveoli are the primary site for gas exchange in the respiratory system. These tiny air sacs in the lungs are where oxygen is taken up into the bloodstream and carbon dioxide is released from the bloodstream into the lungs to be exhaled. The trachea (Choice A) is the windpipe that carries air to and from the lungs but is not directly involved in gas exchange. Bronchioles (Choice B) are smaller airway branches that lead to the alveoli but do not participate in gas exchange themselves. The larynx (Choice D) plays a role in producing sound and protecting the airway but is not primarily responsible for gas exchange.
How might an injury to the parietal lobe impact an individual?
- A. Breathing
- B. Attention
- C. Memory
- D. Perception
Correct Answer: D
Rationale: An injury to the parietal lobe can impact an individual's perception, affecting their ability to interpret sensory information such as touch, spatial orientation, and recognizing objects. The parietal lobe is crucial for integrating sensory information and creating a coherent perception of the surrounding world. Damage to this area can lead to challenges with spatial awareness, object recognition, and accurate processing of sensory input. Choices A, B, and C are incorrect because breathing, attention, and memory are primarily associated with other brain regions such as the brainstem, frontal lobe, and temporal lobe respectively, not the parietal lobe.
What are the chemical messengers that control growth, differentiation, and metabolism of specific target cells called?
- A. Hormones
- B. Neurons
- C. Glands
- D. Second messengers
Correct Answer: A
Rationale: Hormones are signaling molecules produced by glands in multicellular organisms. They travel through the bloodstream to specific target cells where they regulate various physiological processes, including growth, differentiation, and metabolism. Neurons (choice B) are nerve cells that transmit nerve impulses and are not responsible for controlling growth, differentiation, or metabolism. Glands (choice C) produce and release hormones but are not the chemical messengers themselves. Second messengers (choice D) are molecules involved in intracellular signal transduction, not the primary chemical messengers controlling growth, differentiation, and metabolism. Therefore, hormones (choice A) are the correct answer as they match the description provided in the question.