2. Digestion and absorption

What is digestion?

The hydrolysis of larger insoluable molecules into smaller molecules that can be absorbed across cell membranes

What enzymes are involved in carbohydrate digestion?

Amalayse, maltase, sucrase, lactase

What are the substrate an products of carbohydrate digestive enzymes?

Amylase - smaller polysccharides

Maltase - 2 glucose

Sucrase - glucose and fructose

Lactase - glucose and galactose

Where are lipids digested?

Small intestine

What happens to lipids before they can be digested?

Emuslified by bile salts produced in the liver. This breaks down large fat molecules into smaller, soluable molecules called micelles increasing surface area

How are lipids digested?

Lipase hydrolyses the ester bond between the monoglycerides and fatty acids

What enzymes are involved in protein digestion?

Endopeptidases, Exopeptidases, Dipeptidases

What are endopeptidases role in digestion?

To break down between specific amino acids in the middle of a polypeptide

What are exopeptidases role in digestion?

Break down between specific amino acids at the end of a polypeptide

What are dipeptidases role in digestion?

Break dipeptides into amino acids

How can molecules be absorbed to the ileum aginst the conc gradient?

Co-transport

What molecules require co-transport?

Amino acids and monosaccharides

How are sodium ions are involved in co-transport?

Sodium ions are actively transported out of the cell into the lumin creating a diffusion gradient.

Why do fatty acids and monoglycerides not require co-transport?

The molecules are nonpolar, meaning they can easily diffuse across the membrane of the epithelial