What is the role of enzymes in the body?

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.

Correct Answer: A

Rationale: The spleen plays a crucial role in the lymphatic system by filtering blood, specifically removing old or damaged red blood cells. Additionally, the spleen produces lymphocytes, a type of white blood cell that plays a key role in the immune response by helping to fight off infections. Therefore, the correct answer is A, as the spleen is primarily involved in blood filtration and the production of lymphocytes rather than storing vitamins or regulating body temperature.

Correct Answer: B

Rationale: The medulla oblongata, situated in the brainstem, plays a crucial role in controlling essential functions like heart rate, blood pressure, and breathing. It contains vital cardiovascular and respiratory centers, making it the correct choice for the regulation of heart rate and blood pressure. The cerebellum is primarily involved in coordinating movement and balance, not in regulating heart rate and blood pressure. The hypothalamus is responsible for maintaining homeostasis, regulating body temperature, hunger, and thirst, but not specifically heart rate and blood pressure. The pons is involved in functions like sleep, respiration, and bladder control, not primarily in regulating heart rate and blood pressure.

Correct Answer: B

Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.

Correct Answer: B

Rationale: The correct answer is B: Occipital lobe. The occipital lobe, situated at the back of the brain, is specifically responsible for processing visual information received from the eyes. It plays a crucial role in interpreting and making sense of visual stimuli, allowing individuals to perceive and comprehend the world around them. The Temporal lobe (Choice A) is involved in processing auditory information and memory, not visual processing. The Parietal lobe (Choice C) is responsible for processing sensory information from various parts of the body, but not specifically visual information. The Frontal lobe (Choice D) is involved in functions such as decision-making, problem-solving, and voluntary movement, but not processing visual stimuli.

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.

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.

Correct Answer: B

Rationale: The larynx is an essential organ of the respiratory system. It plays a crucial role in producing sound, protecting the trachea from food aspiration, and regulating the airflow to and from the lungs. The brain is part of the nervous system, the urethra is part of the urinary system, and the pancreas is part of the digestive system. Therefore, they are not directly related to the respiratory system's functions.

Correct Answer: C

Rationale: The correct answer is C. The liver's primary function in detoxification is to convert harmful toxins into less harmful substances. This process helps in safeguarding the body from the adverse effects of toxins and is essential for maintaining overall health. Choices A, B, and D are incorrect because secreting bile, storing glucose, and producing insulin are functions of the liver unrelated to detoxification.