Multiple Choice
In human digestion, which enzymes hydrolyze dietary starch in the mouth and small intestine, respectively?
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9. Carbohydrates
Starch
Multiple Choice
Which enzyme is primarily responsible for hydrolyzing starch into smaller oligosaccharides during digestion?
A
Pepsin
B
Lactase ()
C
Trypsin
D
Amylase (e.g., salivary or pancreatic )
Verified step by step guidance1
Identify the substrate involved in the digestion process, which in this case is starch, a polysaccharide composed of glucose units linked primarily by α-1,4-glycosidic bonds.
Recall that starch digestion begins in the mouth and continues in the small intestine, involving enzymes that specifically hydrolyze α-1,4-glycosidic bonds to break starch into smaller oligosaccharides.
Understand the role of different enzymes: Pepsin and Trypsin are proteases that hydrolyze peptide bonds in proteins, not carbohydrates; Lactase hydrolyzes β-galactosidic bonds in lactose, a disaccharide, not starch.
Focus on amylase enzymes (such as salivary amylase and pancreatic α-amylase), which catalyze the hydrolysis of α-1,4-glycosidic linkages in starch, producing smaller oligosaccharides like maltose and maltotriose.
Conclude that the enzyme primarily responsible for hydrolyzing starch into smaller oligosaccharides during digestion is amylase, due to its specificity for starch and its presence in saliva and pancreatic secretions.
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