Question

Describe in detail the complicated process of how a polymer of carbohydrate is broken down into monomers and absorbed from the small intestine into the blood. x BIVA - AI E E EDED V c o 2 1 12pt x - HTML Editore 5 = Paragraph - Q n

my professor wants a VERY detailed explanation and I am lost!

Answer 1

The process of digestion of carbohydrates starts from the mouth . In the mouth there occurs both chemical and physical digestion.The process of mastication converts the large food particles into smaller ones and the salivary amylase,in the saliva breaks down carbohydrates into maltose and dextrins which are disaccharides.

Minimal carbohydrate digestion takes place in the stomach.It is due to the inactivation of amylase in the acidic environment of stomach.

The chyme is them passed into the small intestine. The pancreas produces the pancreatic juice which contain pancreatic amylase.It breaks down the dextrins into shorter carbohydrate chains.Enzymes secreted by the intestinal villi cells are called disaccharidases.They break down the disaccharides into their respective monosaccharides.Amylase targets the α-1,4 bonds of complex carbohydrates and it cannot break terminal bonds or α-1,6 bonds.

The cells in the small intestine contain many transport proteins in order to absorb the monosaccharides and other nutrients into the blood . Glucose absorption occurs in the small intestine via the SGLT-1 transporter (sodium glucose co-transporter).

• Fructose is absorbed by facilitated diffusion via the GLUT5 transporter .GLUT-5 is present on the apical membrane of the brush border throughout the small intestine with increased density in the proximal small intestine.
• glucose and galactose are absorbed through active transport..
• Liver recieves these monosaccharides like glucose,galactose and fructose.
• The liver converts galactose to glucose and also breaks fructose into smaller carbon-containing units.It also stores glucose as glycogen .