Question

Which types of carbohydrates can not be digested by humans

Answer 1

Digestion of proteins

The digestion of proteins starts in the stomach. There is no digestion of proteins in the mouth as saliva don't have any enzymes for digestion of proteins.

Mucosa of stomach has gastric glands containing 3 types of cells. These cells release their content in stomach. 

Food rests in stomach for about 4-5 hours, then gets mixed with acidic gastric juices by churning movement of muscular wall and is called chyme at this stage.

Gastric juice contains HCl, pepsinogen. Pepsinogen is converted into active form by the action of HCl.

 Proenzyme pepsinogen  Pepsin (active enzyme)

Mucus and bicarbonate lubricate the gastric epithelium and protect it from action of HCl.

Small amount of protein digestion (by pepsin) occurs here.

Rest of the protein digestion occurs in small intestine. Small intestine has  pancreatic juice released by  hepatopancreatic duct which contains inactive enzymes such as trypsinogen, chymotrypsinogen, procarboxypeptidase, amylase, lipase, nuclease, etc.Trypsinogen is converted into active form by enterokinase. This active trpsin then activates other enzymes including chymotripsinogen, procarboxypeptidase.



 

Digestion of fats :  It occurs only in intestine by the action of enzymes. Pancreatic ipase digests fat into diglycerides or monogylcerides, which are further digested into fatty acids and glycerol by intestinal lipases 

 

Answer 2

Cellulose cannot be digested by humans