Digestion and Absorption of Lipids and Carbohydrates Flashcards
Define Digestion
Large biological molecules are hydrolysed by enzymes into molecules that can be absorbed across cell membranes
What happens to polysaccharides in digestion?
Their glycosidic bonds are hydrolysed and they are broken into disaccharides by an enzyme
What happens to disaccharides in digestion?
Their glycosidic bonds are hydrolysed and they are broken into monosaccharides by an enzyme
How is starch digested?
It is hydrolysed into maltose by amylase
How is maltose digested?
It is hydrolysed into alpha glucose by maltase
How is alpha glucose assimilated?
It is absorbed by co-transport with Na+
Where is amylase secreted?
The salivary glands and the pancreas
Where is maltase secreted?
In the small intestine
How is sucrose digested?
It is broken into glucose and fructose by sucrase
How is lactose digested?
It is broken into galactose and glucose by lactase
How are large lipid droplets broken down?
Bile salts are added in the process of emulsification
How are small lipid droplets broken down?
Two ester bonds between fatty acid molecules and glycerol are broken and a monoglyceride and two fatty acids are present as micelles
What are micelles?
Tiny droplets of monoglyceride and fatty acids that release monoglyceride close to the cell surface membrane of an epithelial cell so the monoglycerides can diffuse across the cell surface membrane and into the epithelial cells of the small intestine (diffuse across because they are fat soluble)
