What is the primary mode of CO2 transport in the body?
- A. Bicarbonate
- B. Carbamino compounds
- C. None of these
- D. Plasma
Correct Answer: A
Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.
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Which of the following systems is responsible for transporting blood throughout the body?
- A. Respiratory
- B. Circulatory
- C. Nervous
- D. Digestive
Correct Answer: B
Rationale: The correct answer is B: Circulatory. The circulatory system, made up of the heart, blood vessels, and blood, is responsible for transporting blood throughout the body. It plays a vital role in delivering oxygen, nutrients, hormones, and removing waste products from cells. The respiratory system, on the other hand, is responsible for gas exchange in the lungs. The nervous system transmits signals between different parts of the body, while the digestive system processes food and absorbs nutrients from it. Therefore, choices A, C, and D are incorrect as they are not primarily involved in the transportation of blood throughout the body.
Which of the following is responsible for maintaining the body's circadian rhythm?
- A. Thyroid gland
- B. Pineal gland
- C. Pancreas
- D. Hypothalamus
Correct Answer: B
Rationale: The pineal gland is responsible for maintaining the body's circadian rhythm by producing melatonin. Melatonin is a hormone that helps regulate the sleep-wake cycle and is essential in controlling the body's internal clock. The thyroid gland, although important for metabolism, is not directly involved in regulating circadian rhythms. The pancreas plays a role in blood sugar regulation through insulin production, not in controlling circadian rhythms. The hypothalamus is involved in regulating various bodily functions, but the pineal gland is specifically responsible for the circadian rhythm.
Which of the following molecules is a monosaccharide?
- A. Starch
- B. Glucose
- C. Cellulose
- D. Sucrose
Correct Answer: B
Rationale: Starch is a polysaccharide, not a monosaccharide, making choice A incorrect. Glucose, choice B, is the correct answer as it is a monosaccharide, the simplest form of sugar. Cellulose, choice C, is a polysaccharide like starch, not a monosaccharide. Sucrose, choice D, is a disaccharide composed of glucose and fructose, not a monosaccharide. Glucose, being a monosaccharide, is a single sugar unit that serves as a primary energy source for living organisms.
What do lacteals absorb in the small intestine?
- A. Carbohydrates
- B. Lipids
- C. Proteins
- D. Nonpolar nutrients
Correct Answer: B
Rationale: Lacteals are lymphatic capillaries in the small intestine that specialize in absorbing dietary lipids. These lipids are then transported into the lymphatic system for further processing and distribution throughout the body. Choice A (Carbohydrates) is incorrect because carbohydrates are primarily digested and absorbed in the small intestine by enzymes and transported to the liver. Choice C (Proteins) is incorrect because proteins are broken down into amino acids and absorbed in the small intestine, mainly by the villi. Choice D (Nonpolar nutrients) is incorrect as it is a vague term and not specific to what lacteals absorb, which are primarily lipids.
Which of the following glands is responsible for regulating metabolism?
- A. Thymus
- B. Pituitary
- C. Pancreas
- D. Thyroid
Correct Answer: D
Rationale: The correct answer is D, Thyroid. The thyroid gland is responsible for regulating metabolism by producing thyroid hormones. These hormones play a crucial role in controlling various metabolic processes in the body, including energy production and utilization. Choice A, Thymus, is not responsible for regulating metabolism but plays a role in the immune system. Choice B, Pituitary, regulates various hormones but not specifically focused on metabolism. Choice C, Pancreas, is involved in insulin production and blood sugar regulation but is not primarily responsible for regulating metabolism.