Nokea
What is the role of enzymes in the body?
- A. To produce energy
- B. To speed up chemical reactions
- C. To transport molecules
- D. To repair tissues
Correct Answer: B
Rationale: Enzymes are biological catalysts that facilitate and speed up chemical reactions in the body. They do not produce energy but enable various processes such as digestion and metabolism by lowering the activation energy required for reactions to occur. Choice A is incorrect because enzymes do not produce energy themselves but assist in energy production through reactions. Choice C is incorrect as enzymes do not primarily function in transporting molecules, although some may have a role in specific transport processes. Choice D is incorrect as the primary role of enzymes is not to repair tissues, but rather to catalyze biochemical reactions.
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What is the role of the stomach in digestion?
- A. To absorb nutrients
- B. To break down food
- C. To secrete digestive enzymes
- D. To transport nutrients
Correct Answer: B
Rationale: The correct answer is B: To break down food. The stomach's primary function in digestion is to mechanically and chemically break down food. It achieves this by utilizing gastric acid and digestive enzymes to convert food into chyme, a semi-liquid mixture. The chyme is then passed to the small intestine for further processing and absorption of nutrients. Choices A, C, and D are incorrect because the stomach's main role is not to absorb nutrients, secrete digestive enzymes, or transport nutrients; instead, it primarily focuses on breaking down food.
Which of the following is not a principal organ of the nervous system?
- A. Brain
- B. Thymus
- C. Ganglia
- D. Spinal cord
Correct Answer: B
Rationale: The correct answer is B. The thymus is not a principal organ of the nervous system; it is part of the immune system. The brain, spinal cord, and ganglia are principal organs of the nervous system. The brain is responsible for processing information, the spinal cord helps transmit signals between the brain and the rest of the body, and ganglia are clusters of nerve cells that support the nervous system's functions. Therefore, the thymus is the correct answer as it is not directly involved in nervous system functions.
What is the function of the urinary bladder?
- A. To filter waste from the blood
- B. To store urine
- C. To regulate fluid balance
- D. To remove waste from the body
Correct Answer: B
Rationale: The correct answer is B: To store urine. The urinary bladder's primary function is to store urine produced by the kidneys until it is ready to be excreted from the body. It acts as a reservoir that temporarily holds urine until an appropriate time for elimination. Choices A, C, and D are incorrect because the urinary bladder does not filter waste from the blood, regulate fluid balance, or directly remove waste from the body. These functions are primarily carried out by the kidneys and other organs in the excretory system.
What is the main function of white blood cells?
- A. To carry oxygen
- B. To fight infections
- C. To carry nutrients
- D. To remove waste products
Correct Answer: B
Rationale: The main function of white blood cells, also known as leukocytes, is to fight infections and foreign invaders to protect the body from harm. They play a crucial role in the immune system by identifying and destroying pathogens like bacteria and viruses, essential for maintaining the body's health and overall immunity. Choices A, C, and D are incorrect as carrying oxygen is primarily done by red blood cells, carrying nutrients is a function of various body systems, and removing waste products is mainly the role of the kidneys and liver, not white blood cells.
What role does the liver play in metabolism?
- A. Storing glucose
- B. Secreting bile
- C. Detoxifying harmful substances
- D. Producing enzymes
Correct Answer: D
Rationale: The correct answer is D: Producing enzymes. The liver is involved in metabolism by producing enzymes that are essential for regulating various metabolic processes in the body. While the liver does store glucose, secrete bile, and detoxify harmful substances, its primary role in metabolism is producing enzymes that facilitate biochemical reactions necessary for energy production, nutrient breakdown, and waste elimination. Choices A, B, and C are incorrect because although the liver performs these functions, they are not directly related to its primary role in metabolism, which is producing enzymes.