Q41. Which of the following is NOT a characteristic of viruses?
a) Presence of a cellular structure
b) Ability to infect host cells
c) Genetic material either DNA or RNA
d) Dependence on a host for replication
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Correct Answer: a) Presence of a cellular structure
Explanation: Unlike cells, viruses lack a cellular structure. They consist of genetic material (either DNA or RNA) surrounded by a protein coat called a capsid. Some viruses may also have an outer lipid envelope derived from the host cell’s membrane. Viruses are obligate intracellular parasites, meaning they cannot replicate independently and rely on host cells for replication and propagation.
Q42. What is the function of the enzyme lactase in the digestive system?
a) Breakdown of lipids
b) Breakdown of proteins
c) Breakdown of lactose
d) Absorption of nutrients
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Correct Answer: c) Breakdown of lactose
Explanation: Lactase is an enzyme produced in the small intestine that catalyzes the breakdown of lactose, a disaccharide found in milk and dairy products, into its component sugars, glucose, and galactose. Individuals who are lactose intolerant lack sufficient lactase activity, leading to digestive symptoms such as bloating, gas, and diarrhea after consuming dairy products.
Q43. What is the role of hemoglobin in the human body?
a) Transport of oxygen
b) Transport of carbon dioxide
c) Blood clotting
d) Immune response
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Correct Answer: a) Transport of oxygen
Explanation: Hemoglobin is a protein found in red blood cells that plays a crucial role in oxygen transport throughout the body. It binds to oxygen molecules in the lungs, where oxygen levels are high, and releases them in tissues with lower oxygen concentrations. This process ensures that oxygen is efficiently delivered to cells for cellular respiration, where it is used to generate energy.
Q44. What is the function of the enzyme amylase in the digestive system?
a) Breakdown of lipids
b) Breakdown of proteins
c) Breakdown of carbohydrates
d) Absorption of nutrients
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Correct Answer: c) Breakdown of carbohydrates
Explanation: Amylase is an enzyme produced by the salivary glands and pancreas that catalyzes the breakdown of complex carbohydrates, such as starch and glycogen, into simpler sugars like maltose and glucose. This process begins in the mouth, where salivary amylase starts the digestion of carbohydrates, and continues in the small intestine with pancreatic amylase.
Q45. What is the primary function of the kidneys in the human body?
a) Regulation of blood pressure
b) Regulation of body temperature
c) Filtration of blood and excretion of waste products
d) Production of digestive enzymes
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Correct Answer: c) Filtration of blood and excretion of waste products
Explanation: The kidneys are vital organs responsible for filtering blood to remove waste products, excess ions, and water from the body, forming urine. In addition to waste excretion, the kidneys play roles in maintaining electrolyte balance, regulating blood pressure, and producing hormones such as erythropoietin, which stimulates red blood cell production.
Q46. Which of the following is NOT a function of the integumentary system?
a) Protection against physical damage and pathogens
b) Regulation of body temperature
c) Production of hormones
d) Sensation of touch, pressure, and temperature
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Correct Answer: c) Production of hormones
Explanation: The integumentary system primarily serves as the body’s first line of defense, protecting against physical damage, pathogens, and dehydration. It also plays a crucial role in regulating body temperature through processes such as sweating and dilation or constriction of blood vessels in the skin. Additionally, the skin contains sensory receptors that allow for the perception of touch, pressure, temperature, and pain. However, hormone production is primarily associated with endocrine glands such as the pituitary, thyroid, and adrenal glands, not the integumentary system.
Q47. What is the function of the enzyme pepsin in the digestive system?
a) Breakdown of lipids
b) Breakdown of proteins
c) Breakdown of carbohydrates
d) Absorption of nutrients
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Correct Answer: b) Breakdown of proteins
Explanation: Pepsin is an enzyme produced in the stomach that plays a key role in the digestion of proteins. It functions by breaking down proteins into smaller peptides through hydrolysis, a process that involves the addition of water molecules to peptide bonds. Pepsin works optimally in the acidic environment of the stomach and is activated from its precursor form, pepsinogen, by gastric acid.
Q48. What is the function of the enzyme lipase in the digestive system?
a) Breakdown of lipids
b) Breakdown of proteins
c) Breakdown of carbohydrates
d) Absorption of nutrients
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Correct Answer: a) Breakdown of lipids
Explanation: Lipase is an enzyme responsible for the hydrolysis of dietary fats (lipids) into fatty acids and glycerol, which can be absorbed by the small intestine. It is produced by the pancreas and secreted into the small intestine, where it acts on triglycerides present in ingested food, breaking them down into smaller molecules that can be absorbed by intestinal cells and utilized for energy or stored as fat.
Q49. Which of the following is NOT a function of the nervous system?
a) Regulation of body temperature
b) Coordination of movement
c) Perception of sensory stimuli
d) Control of physiological processes
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Correct Answer: a) Regulation of body temperature
Explanation: While the nervous system plays a vital role in coordinating movement, perceiving sensory stimuli, and controlling various physiological processes through the integration and transmission of nerve impulses, regulation of body temperature primarily involves the integumentary system (skin) and thermoregulatory mechanisms such as sweating, shivering, and vasodilation or constriction of blood vessels.
Q50. What is the function of the enzyme trypsin in the digestive system?
a) Breakdown of lipids
b) Breakdown of proteins
c) Breakdown of carbohydrates
d) Absorption of nutrients
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Correct Answer: b) Breakdown of proteins
Explanation: Trypsin is an enzyme produced in the pancreas and involved in the digestion of proteins in the small intestine. It functions by hydrolyzing peptide bonds between specific amino acids, breaking down proteins into smaller peptides and amino acids that can be absorbed by the intestinal epithelium. Trypsin works synergistically with other pancreatic enzymes, such as chymotrypsin and carboxypeptidase, to complete protein digestion.