Digestion and absorption flashcards

What are the main types of carbohydrates involved in digestion?

Disaccharides (sucrose, lactose, maltose) and polysaccharides (starch, glycogen, cellulose).

Which carbohydrates must be converted into monosaccharides for absorption?

Disaccharides and polysaccharides must be digested into monosaccharides.

What enzyme breaks down starch and glycogen into maltose?

Amylase.

What are the products of maltose digestion?

2 glucose molecules.

How is fructose absorbed in the intestinal cells?

Fructose is transported by facilitated diffusion via the GLUT5 transporter.

Which transporters are involved in the absorption of glucose and galactose?

Secondary active transport via the SGLT symporter.

What is the role of the Na+/K+ pump in nutrient absorption?

It maintains the sodium gradient necessary for the SGLT symporter function.

What are the types of proteins that are digested in the gastrointestinal tract?

Dietary proteins, secretions into the GI tract lumen, and cell debris.

What types of proteases are involved in protein digestion?

Endopeptidases (e.g., trypsin, chymotrypsin) and exopeptidases (e.g., carboxypeptidase, aminopeptidase).

What is the function of enterokinase in protein digestion?

It activates trypsin, an endopeptidase.

How do amino acids get absorbed into intestinal epithelial cells?

By active transport through sodium cotransport across the apical membrane.

What happens to dipeptides and tripeptides once inside epithelial cells?

They are further broken down by proteases into amino acids.

Why is lipid digestion considered complex?

Because lipids are insoluble in water and require emulsification by bile salts.

What role do bile salts play in the digestion of lipids?

They emulsify larger fat droplets into smaller droplets, increasing surface area.

What are the end products of fat digestion?

Monoglycerides and fatty acids.

What are chylomicrons?

Lipid-protein complexes formed in intestinal cells that transport absorbed fats into the lymphatic system.

How are carbohydrates ultimately absorbed into the blood?

By being digested into monosaccharides.

What are the primary products of protein breakdown?

Amino acids, dipeptides, and tripeptides.

What is required for lipid digestion and transport?

Bile salts to emulsify fat droplets.