Digestion & Absorption of Carbohydrates

How are carbohydrates in foodstuffs broken down into simple sugars in the GI tract?

• Carbohydrates are absorbed directly into the bloodstream without any breakdown.
• Simple sugars are formed only in the stomach through acid digestion.
• Carbohydrates are broken down into simple sugars through enzymatic hydrolysis by salivary amylase, pancreatic amylase, and brush border enzymes in the GI tract.
• Carbohydrates are converted to fats before being broken down into sugars.

Which of the following are disorders of sugar hydrolysis and absorption?

• Fructose malabsorption
• Sucrose-isomaltase deficiency.

• Galactosemia
• Maltase deficiency

How do monosaccharides transport into blood circulation?

• Monosaccharides are only transported through simple diffusion.
• Monosaccharides are absorbed directly into the bloodstream without transporters.
• Monosaccharides are transported exclusively by passive transport mechanisms.
• Monosaccharides are transported via facilitated diffusion and active transport, primarily using SGLT1 and GLUT5.

Priya is curious about how carbohydrates are broken down in the GIT after eating. Can you briefly explain the hydrolysis of carbohydrates to her?

• Carbohydrates are converted into proteins and fats.

• Carbohydrates are hydrolyzed into monosaccharides through enzymatic action.

• Carbohydrates are absorbed directly into the bloodstream without any breakdown.
• Carbohydrates are stored as fats immediately after ingestion.

What are the roles of insulin and glucagon in blood sugar homesotasis?

• Insulin lowers blood sugar; glucagon raises blood sugar.
• Insulin has no effect on blood sugar; glucagon stabilizes it.
• Insulin and glucagon both lower blood sugar levels.

Answer explanation

Glucose regulation involves insulin and glucagon. Insulin lowers blood sugar by facilitating glucose uptake, while glucagon raises it by promoting glycogen breakdown. This balance maintains homeostasis in energy levels.

What are the polysaccharides involved in digestion?

• Starch & glycogen

• Sucrose, lactose, maltose

• Fructose, pentose

What enzyme is responsible for the hydrolysis of starch in the mouth?

• Ptyalin

• Amylopsin

• Lactase

• Sucrase

What happens to carbohydrate digestion in the stomach?

• Lingual amylase further break down the dextrin

• Disaccharides hydrolysis may occurs

• No carbohydrate splitting enzymes available

• HCl may hydrolyzes the carbohydrates

What is the role of amylopsin (pancreatic amylase) in carbohydrate digestion?

• It hydrolyzes α-1→4 glycosidic linkage

• It cleaves lactose

• It is inactive in the duodenum

• It requires a low pH for activation

What is the primary site of monosaccharide absorption?

• Duodenum

• Upper jejunum

• Distal ileum

• Large intestine