{ "chapter": "Digestion", "count": 100, "answerIndex": "zero-based", "notice": "Original practice items including related concept variants; not official examination questions.", "questions": [ { "id": "bile-duct-blockage", "chapter": "Digestion", "difficulty": "Standard", "stem": "A bile duct is completely blocked while pancreatic secretion remains normal. Absorption of which nutrient class should decline most sharply?", "options": [ "Lipids", "Amino acids", "Monosaccharides", "Mineral ions" ], "answer": 0, "explanation": "Bile salts emulsify fats and help form micelles, increasing access for lipase and carrying lipid digestion products to the intestinal surface." }, { "id": "pepsin-small-intestine", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Why does pepsin lose most of its activity after acidic chyme enters the small intestine?", "options": [ "Pepsin is converted into bile", "Bicarbonate raises the pH away from pepsin's optimum", "All proteins have already been absorbed in the stomach", "The small intestine contains no water" ], "answer": 1, "explanation": "Pancreatic bicarbonate neutralizes gastric acid. Pepsin is adapted to strongly acidic conditions, so the higher intestinal pH reduces its activity." }, { "id": "villus-lacteal", "chapter": "Digestion", "difficulty": "Standard", "stem": "Damage limited to the lacteals inside intestinal villi would most directly reduce the transport of:", "options": [ "Glucose into blood capillaries", "Amino acids into the hepatic portal vein", "Chylomicrons into the lymphatic system", "Water by osmosis" ], "answer": 2, "explanation": "Absorbed long-chain lipids are repackaged as chylomicrons and enter lacteals, whereas most sugars and amino acids enter blood capillaries." }, { "id": "sodium-glucose-cotransport", "chapter": "Digestion", "difficulty": "Challenge", "stem": "The sodium–potassium pumps of intestinal epithelial cells stop. Which absorptive process should weaken as the sodium gradient collapses?", "options": [ "Simple diffusion of lipid-soluble molecules", "Emulsification by bile salts", "Hydrolysis of proteins in the stomach", "Sodium–glucose co-transport from the lumen" ], "answer": 3, "explanation": "The basolateral sodium–potassium pump maintains the sodium gradient that powers secondary active co-transport of sodium and glucose across the apical membrane." }, { "id": "digestion-chewing-outcome", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Food is broken into smaller pieces by chewing. Which outcome follows most directly?", "options": [ "The rate of subsequent enzyme digestion can increase", "Some starch is hydrolysed to maltose", "The bolus is propelled forward", "Pepsin gains a suitable pH and many swallowed microbes are killed" ], "answer": 0, "explanation": "The rate of subsequent enzyme digestion can increase. Mechanical breakdown exposes a greater surface area to digestive secretions." }, { "id": "digestion-chewing-cause", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which change most directly explains this observation: the rate of subsequent enzyme digestion can increase?", "options": [ "Salivary amylase mixes with cooked starch in the mouth", "Food is broken into smaller pieces by chewing", "Circular muscle contracts behind a food bolus in the alimentary canal", "Hydrochloric acid is secreted into the stomach" ], "answer": 1, "explanation": "The rate of subsequent enzyme digestion can increase. Mechanical breakdown exposes a greater surface area to digestive secretions." }, { "id": "digestion-chewing-mechanism", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After food is broken into smaller pieces by chewing, which explanation best links the change to its outcome?", "options": [ "The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH", "Coordinated waves of contraction and relaxation generate peristalsis", "Mechanical breakdown exposes a greater surface area to digestive secretions", "The acid creates a strongly acidic lumen and helps activate pepsinogen" ], "answer": 2, "explanation": "The rate of subsequent enzyme digestion can increase. Mechanical breakdown exposes a greater surface area to digestive secretions." }, { "id": "digestion-salivary-amylase-outcome", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After salivary amylase mixes with cooked starch in the mouth, which observation is most likely?", "options": [ "The bolus is propelled forward", "Lipase digests the fat more rapidly", "Pepsin gains a suitable pH and many swallowed microbes are killed", "Some starch is hydrolysed to maltose" ], "answer": 3, "explanation": "Some starch is hydrolysed to maltose. The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH." }, { "id": "digestion-salivary-amylase-cause", "chapter": "Digestion", "difficulty": "Foundation", "stem": "A learner records that some starch is hydrolysed to maltose. Which preceding event best accounts for it?", "options": [ "Salivary amylase mixes with cooked starch in the mouth", "Hydrochloric acid is secreted into the stomach", "Circular muscle contracts behind a food bolus in the alimentary canal", "Bile salts disperse a large fat droplet" ], "answer": 0, "explanation": "Some starch is hydrolysed to maltose. The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH." }, { "id": "digestion-salivary-amylase-mechanism", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After salivary amylase mixes with cooked starch in the mouth, which explanation best links the change to its outcome?", "options": [ "Coordinated waves of contraction and relaxation generate peristalsis", "The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH", "Emulsification creates many small droplets with a greater enzyme-accessible surface", "The acid creates a strongly acidic lumen and helps activate pepsinogen" ], "answer": 1, "explanation": "Some starch is hydrolysed to maltose. The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH." }, { "id": "digestion-salivary-amylase-integrated", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: salivary amylase mixes with cooked starch in the mouth?", "options": [ "Pepsin gains a suitable pH and many swallowed microbes are killed — The acid creates a strongly acidic lumen and helps activate pepsinogen", "The bolus is propelled forward — Coordinated waves of contraction and relaxation generate peristalsis", "Some starch is hydrolysed to maltose — The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH", "Lipase digests the fat more rapidly — Emulsification creates many small droplets with a greater enzyme-accessible surface" ], "answer": 2, "explanation": "Some starch is hydrolysed to maltose. The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH." }, { "id": "digestion-peristalsis-outcome", "chapter": "Digestion", "difficulty": "Foundation", "stem": "A student models this change: Circular muscle contracts behind a food bolus in the alimentary canal. What should the model predict first?", "options": [ "Pepsin gains a suitable pH and many swallowed microbes are killed", "Lipase digests the fat more rapidly", "Nutrients are absorbed efficiently", "The bolus is propelled forward" ], "answer": 3, "explanation": "The bolus is propelled forward. Coordinated waves of contraction and relaxation generate peristalsis." }, { "id": "digestion-peristalsis-cause", "chapter": "Digestion", "difficulty": "Foundation", "stem": "What is the most likely cause when the bolus is propelled forward?", "options": [ "Circular muscle contracts behind a food bolus in the alimentary canal", "Bile salts disperse a large fat droplet", "The small intestine has folds, villi and microvilli", "Hydrochloric acid is secreted into the stomach" ], "answer": 0, "explanation": "The bolus is propelled forward. Coordinated waves of contraction and relaxation generate peristalsis." }, { "id": "digestion-peristalsis-mechanism", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After circular muscle contracts behind a food bolus in the alimentary canal, which explanation best links the change to its outcome?", "options": [ "The acid creates a strongly acidic lumen and helps activate pepsinogen", "Coordinated waves of contraction and relaxation generate peristalsis", "Emulsification creates many small droplets with a greater enzyme-accessible surface", "These structures greatly enlarge the epithelial surface available for transport" ], "answer": 1, "explanation": "The bolus is propelled forward. Coordinated waves of contraction and relaxation generate peristalsis." }, { "id": "digestion-peristalsis-integrated", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: circular muscle contracts behind a food bolus in the alimentary canal?", "options": [ "Pepsin gains a suitable pH and many swallowed microbes are killed — The acid creates a strongly acidic lumen and helps activate pepsinogen", "Lipase digests the fat more rapidly — Emulsification creates many small droplets with a greater enzyme-accessible surface", "The bolus is propelled forward — Coordinated waves of contraction and relaxation generate peristalsis", "Nutrients are absorbed efficiently — These structures greatly enlarge the epithelial surface available for transport" ], "answer": 2, "explanation": "The bolus is propelled forward. Coordinated waves of contraction and relaxation generate peristalsis." }, { "id": "digestion-gastric-acid-outcome", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which immediate result is most consistent with this condition: Hydrochloric acid is secreted into the stomach?", "options": [ "Lipase digests the fat more rapidly", "Nutrients are absorbed efficiently", "Its epithelium is protected from acid and pepsin", "Pepsin gains a suitable pH and many swallowed microbes are killed" ], "answer": 3, "explanation": "Pepsin gains a suitable pH and many swallowed microbes are killed. The acid creates a strongly acidic lumen and helps activate pepsinogen." }, { "id": "digestion-gastric-acid-cause", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which condition would most specifically produce this result: pepsin gains a suitable pH and many swallowed microbes are killed?", "options": [ "Hydrochloric acid is secreted into the stomach", "Bile salts disperse a large fat droplet", "The small intestine has folds, villi and microvilli", "The stomach secretes a bicarbonate-rich mucus layer" ], "answer": 0, "explanation": "Pepsin gains a suitable pH and many swallowed microbes are killed. The acid creates a strongly acidic lumen and helps activate pepsinogen." }, { "id": "digestion-gastric-acid-mechanism", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After hydrochloric acid is secreted into the stomach, which explanation best links the change to its outcome?", "options": [ "Emulsification creates many small droplets with a greater enzyme-accessible surface", "The acid creates a strongly acidic lumen and helps activate pepsinogen", "These structures greatly enlarge the epithelial surface available for transport", "The barrier limits enzyme contact and maintains a less acidic pH at the cell surface" ], "answer": 1, "explanation": "Pepsin gains a suitable pH and many swallowed microbes are killed. The acid creates a strongly acidic lumen and helps activate pepsinogen." }, { "id": "digestion-gastric-acid-integrated", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: hydrochloric acid is secreted into the stomach?", "options": [ "Lipase digests the fat more rapidly — Emulsification creates many small droplets with a greater enzyme-accessible surface", "Nutrients are absorbed efficiently — These structures greatly enlarge the epithelial surface available for transport", "Pepsin gains a suitable pH and many swallowed microbes are killed — The acid creates a strongly acidic lumen and helps activate pepsinogen", "Its epithelium is protected from acid and pepsin — The barrier limits enzyme contact and maintains a less acidic pH at the cell surface" ], "answer": 2, "explanation": "Pepsin gains a suitable pH and many swallowed microbes are killed. The acid creates a strongly acidic lumen and helps activate pepsinogen." }, { "id": "digestion-bile-emulsion-outcome", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Bile salts disperse a large fat droplet. Which outcome follows most directly?", "options": [ "Protein digestion does not begin inside the secretory cells", "Nutrients are absorbed efficiently", "Its epithelium is protected from acid and pepsin", "Lipase digests the fat more rapidly" ], "answer": 3, "explanation": "Lipase digests the fat more rapidly. Emulsification creates many small droplets with a greater enzyme-accessible surface." }, { "id": "digestion-bile-emulsion-cause", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which change most directly explains this observation: lipase digests the fat more rapidly?", "options": [ "Bile salts disperse a large fat droplet", "The small intestine has folds, villi and microvilli", "The stomach secretes a bicarbonate-rich mucus layer", "Chief cells release pepsin as inactive pepsinogen" ], "answer": 0, "explanation": "Lipase digests the fat more rapidly. Emulsification creates many small droplets with a greater enzyme-accessible surface." }, { "id": "digestion-bile-emulsion-mechanism", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After bile salts disperse a large fat droplet, which explanation best links the change to its outcome?", "options": [ "These structures greatly enlarge the epithelial surface available for transport", "Emulsification creates many small droplets with a greater enzyme-accessible surface", "The barrier limits enzyme contact and maintains a less acidic pH at the cell surface", "Activation occurs mainly after the zymogen reaches the acidic stomach lumen" ], "answer": 1, "explanation": "Lipase digests the fat more rapidly. Emulsification creates many small droplets with a greater enzyme-accessible surface." }, { "id": "digestion-bile-emulsion-integrated", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: bile salts disperse a large fat droplet?", "options": [ "Nutrients are absorbed efficiently — These structures greatly enlarge the epithelial surface available for transport", "Its epithelium is protected from acid and pepsin — The barrier limits enzyme contact and maintains a less acidic pH at the cell surface", "Lipase digests the fat more rapidly — Emulsification creates many small droplets with a greater enzyme-accessible surface", "Protein digestion does not begin inside the secretory cells — Activation occurs mainly after the zymogen reaches the acidic stomach lumen" ], "answer": 2, "explanation": "Lipase digests the fat more rapidly. Emulsification creates many small droplets with a greater enzyme-accessible surface." }, { "id": "digestion-villus-area-outcome", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After the small intestine has folds, villi and microvilli, which observation is most likely?", "options": [ "Its epithelium is protected from acid and pepsin", "Acidic chyme becomes neutralized", "Protein digestion does not begin inside the secretory cells", "Nutrients are absorbed efficiently" ], "answer": 3, "explanation": "Nutrients are absorbed efficiently. These structures greatly enlarge the epithelial surface available for transport." }, { "id": "digestion-villus-area-cause", "chapter": "Digestion", "difficulty": "Foundation", "stem": "A learner records that nutrients are absorbed efficiently. Which preceding event best accounts for it?", "options": [ "The small intestine has folds, villi and microvilli", "Chief cells release pepsin as inactive pepsinogen", "The stomach secretes a bicarbonate-rich mucus layer", "Bicarbonate-rich pancreatic juice enters the duodenum" ], "answer": 0, "explanation": "Nutrients are absorbed efficiently. These structures greatly enlarge the epithelial surface available for transport." }, { "id": "digestion-villus-area-mechanism", "chapter": "Digestion", "difficulty": "Foundation", "stem": "After the small intestine has folds, villi and microvilli, which explanation best links the change to its outcome?", "options": [ "The barrier limits enzyme contact and maintains a less acidic pH at the cell surface", "These structures greatly enlarge the epithelial surface available for transport", "Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes", "Activation occurs mainly after the zymogen reaches the acidic stomach lumen" ], "answer": 1, "explanation": "Nutrients are absorbed efficiently. These structures greatly enlarge the epithelial surface available for transport." }, { "id": "digestion-villus-area-integrated", "chapter": "Digestion", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: the small intestine has folds, villi and microvilli?", "options": [ "Protein digestion does not begin inside the secretory cells — Activation occurs mainly after the zymogen reaches the acidic stomach lumen", "Its epithelium is protected from acid and pepsin — The barrier limits enzyme contact and maintains a less acidic pH at the cell surface", "Nutrients are absorbed efficiently — These structures greatly enlarge the epithelial surface available for transport", "Acidic chyme becomes neutralized — Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes" ], "answer": 2, "explanation": "Nutrients are absorbed efficiently. These structures greatly enlarge the epithelial surface available for transport." }, { "id": "digestion-mucus-stomach-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "A student models this change: The stomach secretes a bicarbonate-rich mucus layer. What should the model predict first?", "options": [ "Protein digestion does not begin inside the secretory cells", "Acidic chyme becomes neutralized", "A cascade of pancreatic protease activation begins", "Its epithelium is protected from acid and pepsin" ], "answer": 3, "explanation": "Its epithelium is protected from acid and pepsin. The barrier limits enzyme contact and maintains a less acidic pH at the cell surface." }, { "id": "digestion-mucus-stomach-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "What is the most likely cause when its epithelium is protected from acid and pepsin?", "options": [ "The stomach secretes a bicarbonate-rich mucus layer", "Bicarbonate-rich pancreatic juice enters the duodenum", "Enteropeptidase activates trypsinogen in the small intestine", "Chief cells release pepsin as inactive pepsinogen" ], "answer": 0, "explanation": "Its epithelium is protected from acid and pepsin. The barrier limits enzyme contact and maintains a less acidic pH at the cell surface." }, { "id": "digestion-mucus-stomach-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After the stomach secretes a bicarbonate-rich mucus layer, which explanation best links the change to its outcome?", "options": [ "Activation occurs mainly after the zymogen reaches the acidic stomach lumen", "The barrier limits enzyme contact and maintains a less acidic pH at the cell surface", "Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes", "Trypsin cleaves additional trypsinogen and other protease zymogens" ], "answer": 1, "explanation": "Its epithelium is protected from acid and pepsin. The barrier limits enzyme contact and maintains a less acidic pH at the cell surface." }, { "id": "digestion-pepsinogen-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: Chief cells release pepsin as inactive pepsinogen?", "options": [ "Acidic chyme becomes neutralized", "A cascade of pancreatic protease activation begins", "Protein digestion does not begin inside the secretory cells", "Lactose remains in the gut and may cause diarrhoea and gas" ], "answer": 2, "explanation": "Protein digestion does not begin inside the secretory cells. Activation occurs mainly after the zymogen reaches the acidic stomach lumen." }, { "id": "digestion-pepsinogen-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: protein digestion does not begin inside the secretory cells?", "options": [ "A person produces little brush-border lactase", "Bicarbonate-rich pancreatic juice enters the duodenum", "Enteropeptidase activates trypsinogen in the small intestine", "Chief cells release pepsin as inactive pepsinogen" ], "answer": 3, "explanation": "Protein digestion does not begin inside the secretory cells. Activation occurs mainly after the zymogen reaches the acidic stomach lumen." }, { "id": "digestion-pepsinogen-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After chief cells release pepsin as inactive pepsinogen, which explanation best links the change to its outcome?", "options": [ "Activation occurs mainly after the zymogen reaches the acidic stomach lumen", "Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes", "Trypsin cleaves additional trypsinogen and other protease zymogens", "Undigested sugar retains water osmotically and is fermented by intestinal bacteria" ], "answer": 0, "explanation": "Protein digestion does not begin inside the secretory cells. Activation occurs mainly after the zymogen reaches the acidic stomach lumen." }, { "id": "digestion-pepsinogen-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: chief cells release pepsin as inactive pepsinogen?", "options": [ "Acidic chyme becomes neutralized — Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes", "Protein digestion does not begin inside the secretory cells — Activation occurs mainly after the zymogen reaches the acidic stomach lumen", "A cascade of pancreatic protease activation begins — Trypsin cleaves additional trypsinogen and other protease zymogens", "Lactose remains in the gut and may cause diarrhoea and gas — Undigested sugar retains water osmotically and is fermented by intestinal bacteria" ], "answer": 1, "explanation": "Protein digestion does not begin inside the secretory cells. Activation occurs mainly after the zymogen reaches the acidic stomach lumen." }, { "id": "digestion-pancreatic-bicarbonate-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "Bicarbonate-rich pancreatic juice enters the duodenum. Which outcome follows most directly?", "options": [ "Lactose remains in the gut and may cause diarrhoea and gas", "A cascade of pancreatic protease activation begins", "Acidic chyme becomes neutralized", "Glucose can be absorbed from a relatively dilute intestinal lumen" ], "answer": 2, "explanation": "Acidic chyme becomes neutralized. Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes." }, { "id": "digestion-pancreatic-bicarbonate-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which change most directly explains this observation: acidic chyme becomes neutralized?", "options": [ "Enteropeptidase activates trypsinogen in the small intestine", "Sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter", "A person produces little brush-border lactase", "Bicarbonate-rich pancreatic juice enters the duodenum" ], "answer": 3, "explanation": "Acidic chyme becomes neutralized. Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes." }, { "id": "digestion-pancreatic-bicarbonate-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After bicarbonate-rich pancreatic juice enters the duodenum, which explanation best links the change to its outcome?", "options": [ "Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes", "Undigested sugar retains water osmotically and is fermented by intestinal bacteria", "Trypsin cleaves additional trypsinogen and other protease zymogens", "The inward sodium gradient supplies energy for secondary active transport" ], "answer": 0, "explanation": "Acidic chyme becomes neutralized. Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes." }, { "id": "digestion-pancreatic-bicarbonate-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: bicarbonate-rich pancreatic juice enters the duodenum?", "options": [ "A cascade of pancreatic protease activation begins — Trypsin cleaves additional trypsinogen and other protease zymogens", "Acidic chyme becomes neutralized — Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes", "Glucose can be absorbed from a relatively dilute intestinal lumen — The inward sodium gradient supplies energy for secondary active transport", "Lactose remains in the gut and may cause diarrhoea and gas — Undigested sugar retains water osmotically and is fermented by intestinal bacteria" ], "answer": 1, "explanation": "Acidic chyme becomes neutralized. Hydrogen ions react with bicarbonate, producing conditions suitable for intestinal enzymes." }, { "id": "digestion-trypsin-activation-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "After enteropeptidase activates trypsinogen in the small intestine, which observation is most likely?", "options": [ "Lactose remains in the gut and may cause diarrhoea and gas", "Glucose can be absorbed from a relatively dilute intestinal lumen", "A cascade of pancreatic protease activation begins", "It enters down its concentration gradient without direct ATP use" ], "answer": 2, "explanation": "A cascade of pancreatic protease activation begins. Trypsin cleaves additional trypsinogen and other protease zymogens." }, { "id": "digestion-trypsin-activation-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "A learner records that a cascade of pancreatic protease activation begins. Which preceding event best accounts for it?", "options": [ "A person produces little brush-border lactase", "Sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter", "Fructose binds its apical carrier in an intestinal epithelial cell", "Enteropeptidase activates trypsinogen in the small intestine" ], "answer": 3, "explanation": "A cascade of pancreatic protease activation begins. Trypsin cleaves additional trypsinogen and other protease zymogens." }, { "id": "digestion-trypsin-activation-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After enteropeptidase activates trypsinogen in the small intestine, which explanation best links the change to its outcome?", "options": [ "Trypsin cleaves additional trypsinogen and other protease zymogens", "The inward sodium gradient supplies energy for secondary active transport", "Specific facilitated diffusion transports fructose through the membrane", "Undigested sugar retains water osmotically and is fermented by intestinal bacteria" ], "answer": 0, "explanation": "A cascade of pancreatic protease activation begins. Trypsin cleaves additional trypsinogen and other protease zymogens." }, { "id": "digestion-trypsin-activation-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: enteropeptidase activates trypsinogen in the small intestine?", "options": [ "Lactose remains in the gut and may cause diarrhoea and gas — Undigested sugar retains water osmotically and is fermented by intestinal bacteria", "A cascade of pancreatic protease activation begins — Trypsin cleaves additional trypsinogen and other protease zymogens", "Glucose can be absorbed from a relatively dilute intestinal lumen — The inward sodium gradient supplies energy for secondary active transport", "It enters down its concentration gradient without direct ATP use — Specific facilitated diffusion transports fructose through the membrane" ], "answer": 1, "explanation": "A cascade of pancreatic protease activation begins. Trypsin cleaves additional trypsinogen and other protease zymogens." }, { "id": "digestion-lactase-deficiency-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "A student models this change: A person produces little brush-border lactase. What should the model predict first?", "options": [ "Glucose can be absorbed from a relatively dilute intestinal lumen", "It enters down its concentration gradient without direct ATP use", "Lactose remains in the gut and may cause diarrhoea and gas", "They enter blood capillaries and travel first to the liver" ], "answer": 2, "explanation": "Lactose remains in the gut and may cause diarrhoea and gas. Undigested sugar retains water osmotically and is fermented by intestinal bacteria." }, { "id": "digestion-lactase-deficiency-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "What is the most likely cause when lactose remains in the gut and may cause diarrhoea and gas?", "options": [ "Sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter", "Fructose binds its apical carrier in an intestinal epithelial cell", "Amino acids cross the epithelium of an intestinal villus", "A person produces little brush-border lactase" ], "answer": 3, "explanation": "Lactose remains in the gut and may cause diarrhoea and gas. Undigested sugar retains water osmotically and is fermented by intestinal bacteria." }, { "id": "digestion-lactase-deficiency-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After a person produces little brush-border lactase, which explanation best links the change to its outcome?", "options": [ "Undigested sugar retains water osmotically and is fermented by intestinal bacteria", "The inward sodium gradient supplies energy for secondary active transport", "Specific facilitated diffusion transports fructose through the membrane", "Water-soluble products enter portal blood rather than lacteals" ], "answer": 0, "explanation": "Lactose remains in the gut and may cause diarrhoea and gas. Undigested sugar retains water osmotically and is fermented by intestinal bacteria." }, { "id": "digestion-lactase-deficiency-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: a person produces little brush-border lactase?", "options": [ "Glucose can be absorbed from a relatively dilute intestinal lumen — The inward sodium gradient supplies energy for secondary active transport", "Lactose remains in the gut and may cause diarrhoea and gas — Undigested sugar retains water osmotically and is fermented by intestinal bacteria", "It enters down its concentration gradient without direct ATP use — Specific facilitated diffusion transports fructose through the membrane", "They enter blood capillaries and travel first to the liver — Water-soluble products enter portal blood rather than lacteals" ], "answer": 1, "explanation": "Lactose remains in the gut and may cause diarrhoea and gas. Undigested sugar retains water osmotically and is fermented by intestinal bacteria." }, { "id": "digestion-glucose-cotransport-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: Sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter?", "options": [ "It enters down its concentration gradient without direct ATP use", "They enter blood capillaries and travel first to the liver", "Glucose can be absorbed from a relatively dilute intestinal lumen", "They are repackaged and released as chylomicrons into lacteals" ], "answer": 2, "explanation": "Glucose can be absorbed from a relatively dilute intestinal lumen. The inward sodium gradient supplies energy for secondary active transport." }, { "id": "digestion-glucose-cotransport-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: glucose can be absorbed from a relatively dilute intestinal lumen?", "options": [ "Long-chain fatty acids and monoglycerides enter an intestinal epithelial cell", "Fructose binds its apical carrier in an intestinal epithelial cell", "Amino acids cross the epithelium of an intestinal villus", "Sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter" ], "answer": 3, "explanation": "Glucose can be absorbed from a relatively dilute intestinal lumen. The inward sodium gradient supplies energy for secondary active transport." }, { "id": "digestion-glucose-cotransport-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter, which explanation best links the change to its outcome?", "options": [ "The inward sodium gradient supplies energy for secondary active transport", "Specific facilitated diffusion transports fructose through the membrane", "Water-soluble products enter portal blood rather than lacteals", "Triglycerides reform in smooth ER and combine with proteins for lymphatic transport" ], "answer": 0, "explanation": "Glucose can be absorbed from a relatively dilute intestinal lumen. The inward sodium gradient supplies energy for secondary active transport." }, { "id": "digestion-glucose-cotransport-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: sodium enters an intestinal epithelial cell through a sodium-glucose cotransporter?", "options": [ "It enters down its concentration gradient without direct ATP use — Specific facilitated diffusion transports fructose through the membrane", "Glucose can be absorbed from a relatively dilute intestinal lumen — The inward sodium gradient supplies energy for secondary active transport", "They enter blood capillaries and travel first to the liver — Water-soluble products enter portal blood rather than lacteals", "They are repackaged and released as chylomicrons into lacteals — Triglycerides reform in smooth ER and combine with proteins for lymphatic transport" ], "answer": 1, "explanation": "Glucose can be absorbed from a relatively dilute intestinal lumen. The inward sodium gradient supplies energy for secondary active transport." }, { "id": "digestion-fructose-facilitated-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "Fructose binds its apical carrier in an intestinal epithelial cell. Which outcome follows most directly?", "options": [ "They are repackaged and released as chylomicrons into lacteals", "They enter blood capillaries and travel first to the liver", "It enters down its concentration gradient without direct ATP use", "The gallbladder contracts and pancreatic enzyme secretion increases" ], "answer": 2, "explanation": "It enters down its concentration gradient without direct ATP use. Specific facilitated diffusion transports fructose through the membrane." }, { "id": "digestion-fructose-facilitated-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which change most directly explains this observation: it enters down its concentration gradient without direct ATP use?", "options": [ "Amino acids cross the epithelium of an intestinal villus", "Fat enters the duodenum and stimulates cholecystokinin release", "Long-chain fatty acids and monoglycerides enter an intestinal epithelial cell", "Fructose binds its apical carrier in an intestinal epithelial cell" ], "answer": 3, "explanation": "It enters down its concentration gradient without direct ATP use. Specific facilitated diffusion transports fructose through the membrane." }, { "id": "digestion-fructose-facilitated-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After fructose binds its apical carrier in an intestinal epithelial cell, which explanation best links the change to its outcome?", "options": [ "Specific facilitated diffusion transports fructose through the membrane", "Triglycerides reform in smooth ER and combine with proteins for lymphatic transport", "Water-soluble products enter portal blood rather than lacteals", "The hormone coordinates bile delivery with digestion of lipid-rich chyme" ], "answer": 0, "explanation": "It enters down its concentration gradient without direct ATP use. Specific facilitated diffusion transports fructose through the membrane." }, { "id": "digestion-amino-acid-blood-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "After amino acids cross the epithelium of an intestinal villus, which observation is most likely?", "options": [ "They are repackaged and released as chylomicrons into lacteals", "They enter blood capillaries and travel first to the liver", "The gallbladder contracts and pancreatic enzyme secretion increases", "Water and electrolytes are recovered and faeces become more solid" ], "answer": 1, "explanation": "They enter blood capillaries and travel first to the liver. Water-soluble products enter portal blood rather than lacteals." }, { "id": "digestion-amino-acid-blood-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "A learner records that they enter blood capillaries and travel first to the liver. Which preceding event best accounts for it?", "options": [ "Long-chain fatty acids and monoglycerides enter an intestinal epithelial cell", "Fat enters the duodenum and stimulates cholecystokinin release", "Amino acids cross the epithelium of an intestinal villus", "Chyme passes slowly through the large intestine" ], "answer": 2, "explanation": "They enter blood capillaries and travel first to the liver. Water-soluble products enter portal blood rather than lacteals." }, { "id": "digestion-amino-acid-blood-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After amino acids cross the epithelium of an intestinal villus, which explanation best links the change to its outcome?", "options": [ "Triglycerides reform in smooth ER and combine with proteins for lymphatic transport", "The hormone coordinates bile delivery with digestion of lipid-rich chyme", "Epithelial transport creates osmotic water absorption from the remaining contents", "Water-soluble products enter portal blood rather than lacteals" ], "answer": 3, "explanation": "They enter blood capillaries and travel first to the liver. Water-soluble products enter portal blood rather than lacteals." }, { "id": "digestion-amino-acid-blood-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: amino acids cross the epithelium of an intestinal villus?", "options": [ "They enter blood capillaries and travel first to the liver — Water-soluble products enter portal blood rather than lacteals", "They are repackaged and released as chylomicrons into lacteals — Triglycerides reform in smooth ER and combine with proteins for lymphatic transport", "The gallbladder contracts and pancreatic enzyme secretion increases — The hormone coordinates bile delivery with digestion of lipid-rich chyme", "Water and electrolytes are recovered and faeces become more solid — Epithelial transport creates osmotic water absorption from the remaining contents" ], "answer": 0, "explanation": "They enter blood capillaries and travel first to the liver. Water-soluble products enter portal blood rather than lacteals." }, { "id": "digestion-chylomicron-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "A student models this change: Long-chain fatty acids and monoglycerides enter an intestinal epithelial cell. What should the model predict first?", "options": [ "The gallbladder contracts and pancreatic enzyme secretion increases", "They are repackaged and released as chylomicrons into lacteals", "Water and electrolytes are recovered and faeces become more solid", "The liver encounters the nutrient-rich blood before the general circulation" ], "answer": 1, "explanation": "They are repackaged and released as chylomicrons into lacteals. Triglycerides reform in smooth ER and combine with proteins for lymphatic transport." }, { "id": "digestion-chylomicron-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "What is the most likely cause when they are repackaged and released as chylomicrons into lacteals?", "options": [ "Fat enters the duodenum and stimulates cholecystokinin release", "Chyme passes slowly through the large intestine", "Long-chain fatty acids and monoglycerides enter an intestinal epithelial cell", "Absorbed glucose leaves intestinal capillaries through the hepatic portal vein" ], "answer": 2, "explanation": "They are repackaged and released as chylomicrons into lacteals. Triglycerides reform in smooth ER and combine with proteins for lymphatic transport." }, { "id": "digestion-chylomicron-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After long-chain fatty acids and monoglycerides enter an intestinal epithelial cell, which explanation best links the change to its outcome?", "options": [ "Portal circulation permits regulation, storage and detoxification after absorption", "The hormone coordinates bile delivery with digestion of lipid-rich chyme", "Epithelial transport creates osmotic water absorption from the remaining contents", "Triglycerides reform in smooth ER and combine with proteins for lymphatic transport" ], "answer": 3, "explanation": "They are repackaged and released as chylomicrons into lacteals. Triglycerides reform in smooth ER and combine with proteins for lymphatic transport." }, { "id": "digestion-chylomicron-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: long-chain fatty acids and monoglycerides enter an intestinal epithelial cell?", "options": [ "They are repackaged and released as chylomicrons into lacteals — Triglycerides reform in smooth ER and combine with proteins for lymphatic transport", "The gallbladder contracts and pancreatic enzyme secretion increases — The hormone coordinates bile delivery with digestion of lipid-rich chyme", "Water and electrolytes are recovered and faeces become more solid — Epithelial transport creates osmotic water absorption from the remaining contents", "The liver encounters the nutrient-rich blood before the general circulation — Portal circulation permits regulation, storage and detoxification after absorption" ], "answer": 0, "explanation": "They are repackaged and released as chylomicrons into lacteals. Triglycerides reform in smooth ER and combine with proteins for lymphatic transport." }, { "id": "digestion-gallbladder-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: Fat enters the duodenum and stimulates cholecystokinin release?", "options": [ "Water and electrolytes are recovered and faeces become more solid", "The gallbladder contracts and pancreatic enzyme secretion increases", "Absorption of several nutrients declines and malnutrition may develop", "The liver encounters the nutrient-rich blood before the general circulation" ], "answer": 1, "explanation": "The gallbladder contracts and pancreatic enzyme secretion increases. The hormone coordinates bile delivery with digestion of lipid-rich chyme." }, { "id": "digestion-gallbladder-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: the gallbladder contracts and pancreatic enzyme secretion increases?", "options": [ "Absorbed glucose leaves intestinal capillaries through the hepatic portal vein", "Chyme passes slowly through the large intestine", "Fat enters the duodenum and stimulates cholecystokinin release", "Autoimmune damage flattens villi in the small intestine" ], "answer": 2, "explanation": "The gallbladder contracts and pancreatic enzyme secretion increases. The hormone coordinates bile delivery with digestion of lipid-rich chyme." }, { "id": "digestion-gallbladder-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After fat enters the duodenum and stimulates cholecystokinin release, which explanation best links the change to its outcome?", "options": [ "Epithelial transport creates osmotic water absorption from the remaining contents", "Loss of villous surface and transporter-bearing epithelium reduces uptake capacity", "Portal circulation permits regulation, storage and detoxification after absorption", "The hormone coordinates bile delivery with digestion of lipid-rich chyme" ], "answer": 3, "explanation": "The gallbladder contracts and pancreatic enzyme secretion increases. The hormone coordinates bile delivery with digestion of lipid-rich chyme." }, { "id": "digestion-gallbladder-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: fat enters the duodenum and stimulates cholecystokinin release?", "options": [ "The gallbladder contracts and pancreatic enzyme secretion increases — The hormone coordinates bile delivery with digestion of lipid-rich chyme", "The liver encounters the nutrient-rich blood before the general circulation — Portal circulation permits regulation, storage and detoxification after absorption", "Water and electrolytes are recovered and faeces become more solid — Epithelial transport creates osmotic water absorption from the remaining contents", "Absorption of several nutrients declines and malnutrition may develop — Loss of villous surface and transporter-bearing epithelium reduces uptake capacity" ], "answer": 0, "explanation": "The gallbladder contracts and pancreatic enzyme secretion increases. The hormone coordinates bile delivery with digestion of lipid-rich chyme." }, { "id": "digestion-large-intestine-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "Chyme passes slowly through the large intestine. Which outcome follows most directly?", "options": [ "The liver encounters the nutrient-rich blood before the general circulation", "Water and electrolytes are recovered and faeces become more solid", "Absorption of several nutrients declines and malnutrition may develop", "Fat digestion and absorption decline more than carbohydrate digestion" ], "answer": 1, "explanation": "Water and electrolytes are recovered and faeces become more solid. Epithelial transport creates osmotic water absorption from the remaining contents." }, { "id": "digestion-large-intestine-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which change most directly explains this observation: water and electrolytes are recovered and faeces become more solid?", "options": [ "Absorbed glucose leaves intestinal capillaries through the hepatic portal vein", "Autoimmune damage flattens villi in the small intestine", "Chyme passes slowly through the large intestine", "A gallstone blocks the common bile duct" ], "answer": 2, "explanation": "Water and electrolytes are recovered and faeces become more solid. Epithelial transport creates osmotic water absorption from the remaining contents." }, { "id": "digestion-large-intestine-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After chyme passes slowly through the large intestine, which explanation best links the change to its outcome?", "options": [ "Portal circulation permits regulation, storage and detoxification after absorption", "Loss of villous surface and transporter-bearing epithelium reduces uptake capacity", "Bile salts cannot efficiently emulsify lipids or support micelle formation", "Epithelial transport creates osmotic water absorption from the remaining contents" ], "answer": 3, "explanation": "Water and electrolytes are recovered and faeces become more solid. Epithelial transport creates osmotic water absorption from the remaining contents." }, { "id": "digestion-large-intestine-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: chyme passes slowly through the large intestine?", "options": [ "Water and electrolytes are recovered and faeces become more solid — Epithelial transport creates osmotic water absorption from the remaining contents", "Absorption of several nutrients declines and malnutrition may develop — Loss of villous surface and transporter-bearing epithelium reduces uptake capacity", "Fat digestion and absorption decline more than carbohydrate digestion — Bile salts cannot efficiently emulsify lipids or support micelle formation", "The liver encounters the nutrient-rich blood before the general circulation — Portal circulation permits regulation, storage and detoxification after absorption" ], "answer": 0, "explanation": "Water and electrolytes are recovered and faeces become more solid. Epithelial transport creates osmotic water absorption from the remaining contents." }, { "id": "digestion-hepatic-portal-outcome", "chapter": "Digestion", "difficulty": "Standard", "stem": "After absorbed glucose leaves intestinal capillaries through the hepatic portal vein, which observation is most likely?", "options": [ "Absorption of several nutrients declines and malnutrition may develop", "The liver encounters the nutrient-rich blood before the general circulation", "Fat digestion and absorption decline more than carbohydrate digestion", "Proteins, starch and triglycerides remain incompletely digested" ], "answer": 1, "explanation": "The liver encounters the nutrient-rich blood before the general circulation. Portal circulation permits regulation, storage and detoxification after absorption." }, { "id": "digestion-hepatic-portal-cause", "chapter": "Digestion", "difficulty": "Standard", "stem": "A learner records that the liver encounters the nutrient-rich blood before the general circulation. Which preceding event best accounts for it?", "options": [ "Autoimmune damage flattens villi in the small intestine", "A gallstone blocks the common bile duct", "Absorbed glucose leaves intestinal capillaries through the hepatic portal vein", "The exocrine pancreas releases few digestive enzymes" ], "answer": 2, "explanation": "The liver encounters the nutrient-rich blood before the general circulation. Portal circulation permits regulation, storage and detoxification after absorption." }, { "id": "digestion-hepatic-portal-mechanism", "chapter": "Digestion", "difficulty": "Standard", "stem": "After absorbed glucose leaves intestinal capillaries through the hepatic portal vein, which explanation best links the change to its outcome?", "options": [ "Loss of villous surface and transporter-bearing epithelium reduces uptake capacity", "Bile salts cannot efficiently emulsify lipids or support micelle formation", "Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase", "Portal circulation permits regulation, storage and detoxification after absorption" ], "answer": 3, "explanation": "The liver encounters the nutrient-rich blood before the general circulation. Portal circulation permits regulation, storage and detoxification after absorption." }, { "id": "digestion-hepatic-portal-integrated", "chapter": "Digestion", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: absorbed glucose leaves intestinal capillaries through the hepatic portal vein?", "options": [ "The liver encounters the nutrient-rich blood before the general circulation — Portal circulation permits regulation, storage and detoxification after absorption", "Absorption of several nutrients declines and malnutrition may develop — Loss of villous surface and transporter-bearing epithelium reduces uptake capacity", "Fat digestion and absorption decline more than carbohydrate digestion — Bile salts cannot efficiently emulsify lipids or support micelle formation", "Proteins, starch and triglycerides remain incompletely digested — Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase" ], "answer": 0, "explanation": "The liver encounters the nutrient-rich blood before the general circulation. Portal circulation permits regulation, storage and detoxification after absorption." }, { "id": "digestion-coeliac-villi-outcome", "chapter": "Digestion", "difficulty": "Challenge", "stem": "A student models this change: Autoimmune damage flattens villi in the small intestine. What should the model predict first?", "options": [ "Fat digestion and absorption decline more than carbohydrate digestion", "Absorption of several nutrients declines and malnutrition may develop", "Proteins, starch and triglycerides remain incompletely digested", "Large volumes of watery diarrhoea develop" ], "answer": 1, "explanation": "Absorption of several nutrients declines and malnutrition may develop. Loss of villous surface and transporter-bearing epithelium reduces uptake capacity." }, { "id": "digestion-coeliac-villi-cause", "chapter": "Digestion", "difficulty": "Challenge", "stem": "What is the most likely cause when absorption of several nutrients declines and malnutrition may develop?", "options": [ "A gallstone blocks the common bile duct", "The exocrine pancreas releases few digestive enzymes", "Autoimmune damage flattens villi in the small intestine", "Cholera toxin keeps intestinal chloride channels active" ], "answer": 2, "explanation": "Absorption of several nutrients declines and malnutrition may develop. Loss of villous surface and transporter-bearing epithelium reduces uptake capacity." }, { "id": "digestion-coeliac-villi-mechanism", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After autoimmune damage flattens villi in the small intestine, which explanation best links the change to its outcome?", "options": [ "Chloride secretion draws sodium and water osmotically into the intestinal lumen", "Bile salts cannot efficiently emulsify lipids or support micelle formation", "Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase", "Loss of villous surface and transporter-bearing epithelium reduces uptake capacity" ], "answer": 3, "explanation": "Absorption of several nutrients declines and malnutrition may develop. Loss of villous surface and transporter-bearing epithelium reduces uptake capacity." }, { "id": "digestion-duct-block-outcome", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which immediate result is most consistent with this condition: A gallstone blocks the common bile duct?", "options": [ "Fat digestion and absorption decline more than carbohydrate digestion", "Large volumes of watery diarrhoea develop", "Net water absorption improves", "Proteins, starch and triglycerides remain incompletely digested" ], "answer": 0, "explanation": "Fat digestion and absorption decline more than carbohydrate digestion. Bile salts cannot efficiently emulsify lipids or support micelle formation." }, { "id": "digestion-duct-block-cause", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which condition would most specifically produce this result: fat digestion and absorption decline more than carbohydrate digestion?", "options": [ "The exocrine pancreas releases few digestive enzymes", "A gallstone blocks the common bile duct", "Cholera toxin keeps intestinal chloride channels active", "A patient with secretory diarrhoea drinks a balanced glucose-salt solution" ], "answer": 1, "explanation": "Fat digestion and absorption decline more than carbohydrate digestion. Bile salts cannot efficiently emulsify lipids or support micelle formation." }, { "id": "digestion-duct-block-mechanism", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After a gallstone blocks the common bile duct, which explanation best links the change to its outcome?", "options": [ "Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase", "Chloride secretion draws sodium and water osmotically into the intestinal lumen", "Bile salts cannot efficiently emulsify lipids or support micelle formation", "Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen" ], "answer": 2, "explanation": "Fat digestion and absorption decline more than carbohydrate digestion. Bile salts cannot efficiently emulsify lipids or support micelle formation." }, { "id": "digestion-duct-block-integrated", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: a gallstone blocks the common bile duct?", "options": [ "Proteins, starch and triglycerides remain incompletely digested — Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase", "Large volumes of watery diarrhoea develop — Chloride secretion draws sodium and water osmotically into the intestinal lumen", "Net water absorption improves — Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen", "Fat digestion and absorption decline more than carbohydrate digestion — Bile salts cannot efficiently emulsify lipids or support micelle formation" ], "answer": 3, "explanation": "Fat digestion and absorption decline more than carbohydrate digestion. Bile salts cannot efficiently emulsify lipids or support micelle formation." }, { "id": "digestion-pancreatic-insufficiency-outcome", "chapter": "Digestion", "difficulty": "Challenge", "stem": "The exocrine pancreas releases few digestive enzymes. Which outcome follows most directly?", "options": [ "Proteins, starch and triglycerides remain incompletely digested", "Large volumes of watery diarrhoea develop", "Net water absorption improves", "Vitamin B12 and bile-salt absorption are particularly impaired" ], "answer": 0, "explanation": "Proteins, starch and triglycerides remain incompletely digested. Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase." }, { "id": "digestion-pancreatic-insufficiency-cause", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which change most directly explains this observation: proteins, starch and triglycerides remain incompletely digested?", "options": [ "Cholera toxin keeps intestinal chloride channels active", "The exocrine pancreas releases few digestive enzymes", "A patient with secretory diarrhoea drinks a balanced glucose-salt solution", "A large terminal segment of ileum is surgically removed" ], "answer": 1, "explanation": "Proteins, starch and triglycerides remain incompletely digested. Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase." }, { "id": "digestion-pancreatic-insufficiency-mechanism", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After the exocrine pancreas releases few digestive enzymes, which explanation best links the change to its outcome?", "options": [ "Chloride secretion draws sodium and water osmotically into the intestinal lumen", "Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen", "Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase", "Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts" ], "answer": 2, "explanation": "Proteins, starch and triglycerides remain incompletely digested. Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase." }, { "id": "digestion-pancreatic-insufficiency-integrated", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: the exocrine pancreas releases few digestive enzymes?", "options": [ "Large volumes of watery diarrhoea develop — Chloride secretion draws sodium and water osmotically into the intestinal lumen", "Net water absorption improves — Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen", "Vitamin B12 and bile-salt absorption are particularly impaired — Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts", "Proteins, starch and triglycerides remain incompletely digested — Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase" ], "answer": 3, "explanation": "Proteins, starch and triglycerides remain incompletely digested. Most small-intestinal hydrolysis depends on pancreatic proteases, amylase and lipase." }, { "id": "digestion-cholera-outcome", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After cholera toxin keeps intestinal chloride channels active, which observation is most likely?", "options": [ "Large volumes of watery diarrhoea develop", "Net water absorption improves", "Vitamin B12 and bile-salt absorption are particularly impaired", "The rate of subsequent enzyme digestion can increase" ], "answer": 0, "explanation": "Large volumes of watery diarrhoea develop. Chloride secretion draws sodium and water osmotically into the intestinal lumen." }, { "id": "digestion-cholera-cause", "chapter": "Digestion", "difficulty": "Challenge", "stem": "A learner records that large volumes of watery diarrhoea develop. Which preceding event best accounts for it?", "options": [ "A patient with secretory diarrhoea drinks a balanced glucose-salt solution", "Cholera toxin keeps intestinal chloride channels active", "A large terminal segment of ileum is surgically removed", "Food is broken into smaller pieces by chewing" ], "answer": 1, "explanation": "Large volumes of watery diarrhoea develop. Chloride secretion draws sodium and water osmotically into the intestinal lumen." }, { "id": "digestion-cholera-mechanism", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After cholera toxin keeps intestinal chloride channels active, which explanation best links the change to its outcome?", "options": [ "Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen", "Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts", "Chloride secretion draws sodium and water osmotically into the intestinal lumen", "Mechanical breakdown exposes a greater surface area to digestive secretions" ], "answer": 2, "explanation": "Large volumes of watery diarrhoea develop. Chloride secretion draws sodium and water osmotically into the intestinal lumen." }, { "id": "digestion-cholera-integrated", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: cholera toxin keeps intestinal chloride channels active?", "options": [ "The rate of subsequent enzyme digestion can increase — Mechanical breakdown exposes a greater surface area to digestive secretions", "Net water absorption improves — Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen", "Vitamin B12 and bile-salt absorption are particularly impaired — Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts", "Large volumes of watery diarrhoea develop — Chloride secretion draws sodium and water osmotically into the intestinal lumen" ], "answer": 3, "explanation": "Large volumes of watery diarrhoea develop. Chloride secretion draws sodium and water osmotically into the intestinal lumen." }, { "id": "digestion-oral-rehydration-outcome", "chapter": "Digestion", "difficulty": "Challenge", "stem": "A student models this change: A patient with secretory diarrhoea drinks a balanced glucose-salt solution. What should the model predict first?", "options": [ "Net water absorption improves", "The rate of subsequent enzyme digestion can increase", "Vitamin B12 and bile-salt absorption are particularly impaired", "Some starch is hydrolysed to maltose" ], "answer": 0, "explanation": "Net water absorption improves. Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen." }, { "id": "digestion-oral-rehydration-cause", "chapter": "Digestion", "difficulty": "Challenge", "stem": "What is the most likely cause when net water absorption improves?", "options": [ "A large terminal segment of ileum is surgically removed", "A patient with secretory diarrhoea drinks a balanced glucose-salt solution", "Salivary amylase mixes with cooked starch in the mouth", "Food is broken into smaller pieces by chewing" ], "answer": 1, "explanation": "Net water absorption improves. Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen." }, { "id": "digestion-oral-rehydration-mechanism", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After a patient with secretory diarrhoea drinks a balanced glucose-salt solution, which explanation best links the change to its outcome?", "options": [ "Mechanical breakdown exposes a greater surface area to digestive secretions", "Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts", "Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen", "The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH" ], "answer": 2, "explanation": "Net water absorption improves. Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen." }, { "id": "digestion-oral-rehydration-integrated", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: a patient with secretory diarrhoea drinks a balanced glucose-salt solution?", "options": [ "Vitamin B12 and bile-salt absorption are particularly impaired — Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts", "Some starch is hydrolysed to maltose — The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH", "The rate of subsequent enzyme digestion can increase — Mechanical breakdown exposes a greater surface area to digestive secretions", "Net water absorption improves — Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen" ], "answer": 3, "explanation": "Net water absorption improves. Intact sodium-glucose cotransport draws solutes and then water from the intestinal lumen." }, { "id": "digestion-ileum-removal-outcome", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which immediate result is most consistent with this condition: A large terminal segment of ileum is surgically removed?", "options": [ "Vitamin B12 and bile-salt absorption are particularly impaired", "Some starch is hydrolysed to maltose", "The bolus is propelled forward", "The rate of subsequent enzyme digestion can increase" ], "answer": 0, "explanation": "Vitamin B12 and bile-salt absorption are particularly impaired. Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts." }, { "id": "digestion-ileum-removal-cause", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which condition would most specifically produce this result: vitamin B12 and bile-salt absorption are particularly impaired?", "options": [ "Food is broken into smaller pieces by chewing", "A large terminal segment of ileum is surgically removed", "Salivary amylase mixes with cooked starch in the mouth", "Circular muscle contracts behind a food bolus in the alimentary canal" ], "answer": 1, "explanation": "Vitamin B12 and bile-salt absorption are particularly impaired. Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts." }, { "id": "digestion-ileum-removal-mechanism", "chapter": "Digestion", "difficulty": "Challenge", "stem": "After a large terminal segment of ileum is surgically removed, which explanation best links the change to its outcome?", "options": [ "Mechanical breakdown exposes a greater surface area to digestive secretions", "The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH", "Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts", "Coordinated waves of contraction and relaxation generate peristalsis" ], "answer": 2, "explanation": "Vitamin B12 and bile-salt absorption are particularly impaired. Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts." }, { "id": "digestion-ileum-removal-integrated", "chapter": "Digestion", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: a large terminal segment of ileum is surgically removed?", "options": [ "The rate of subsequent enzyme digestion can increase — Mechanical breakdown exposes a greater surface area to digestive secretions", "Some starch is hydrolysed to maltose — The enzyme breaks internal alpha-1,4 glycosidic bonds near neutral pH", "The bolus is propelled forward — Coordinated waves of contraction and relaxation generate peristalsis", "Vitamin B12 and bile-salt absorption are particularly impaired — Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts" ], "answer": 3, "explanation": "Vitamin B12 and bile-salt absorption are particularly impaired. Specialized ileal transporters normally recover intrinsic-factor-bound B12 and recycle bile salts." }, { "chapter": "Digestion", "id": "applied-bile-control", "difficulty": "Challenge", "stem": "A fat-digestion experiment uses identical lipase amounts. Adding bile salts increases digestion rate. Which explanation is best?", "options": [ "Emulsification increases the lipid–water interface accessible to lipase", "Bile salts are protein-digesting enzymes", "Bile salts supply extra lipase molecules", "Bile converts all fat directly into glucose" ], "answer": 0, "explanation": "Bile salts help disperse large fat globules into smaller droplets. More accessible surface assists lipase; emulsification itself does not hydrolyse the triglycerides." }, { "chapter": "Digestion", "id": "applied-absorption-route", "difficulty": "Standard", "stem": "Most long-chain dietary lipids packaged into chylomicrons first enter which structure after leaving intestinal epithelial cells?", "options": [ "Hepatic portal capillaries directly", "Lacteals", "The stomach lumen", "Renal tubules" ], "answer": 1, "explanation": "Chylomicrons enter intestinal lymphatic lacteals before reaching the bloodstream. Many water-soluble nutrients instead enter blood capillaries and the hepatic portal circulation." }, { "chapter": "Digestion", "id": "applied-protease-site", "difficulty": "Standard", "stem": "Which enzyme is most consistent with these results under otherwise controlled conditions?", "options": [ "Pancreatic lipase", "Salivary amylase", "Pepsin", "Maltase" ], "answer": 2, "explanation": "High proteolytic activity in strongly acidic conditions fits pepsin, a stomach protease. The other listed enzymes digest different substrate classes.", "visual": { "kind": "table", "caption": "Protein breakdown by an unknown digestive enzyme", "headers": [ "pH", "Relative activity" ], "rows": [ [ "2", "100" ], [ "7", "5" ], [ "9", "1" ] ] } }, { "chapter": "Digestion", "id": "applied-villus-adaptation", "difficulty": "Foundation", "stem": "Which combination most directly supports rapid absorption of glucose from the small intestine?", "options": [ "A long diffusion distance and a closed blood supply", "A thick keratinised wall and no capillaries", "A smooth inner surface and no transport proteins", "Large surface area, a thin epithelial barrier and good blood supply" ], "answer": 3, "explanation": "Villi and microvilli increase area, while a thin barrier and removal into blood assist transport. Glucose absorption also depends on membrane transport proteins." } ] }