Lipase Acts on

Q. Lipase acts on

1. Amino acid 

2. Carbohydrates 

3. Fats 

4. Protein

Answer:- (3) Fats

Explanation: Lipase acts on fats and performs hydrolysis of fats (not of carbohydrates, fats and proteins).

• Digestion of Fats:- It is carried by Lipases. Digestion of fats starts & completes in the small intestine. In saliva, no fat splitting enzyme is present. Hence, no fat digestion occurs in the oral cavity. Gastric juice of the stomach contains gastric Lipase but its action remains negligible as the PH of the stomach is unfavourable as well as stomach lacks fats emulsifying agents. In the case of infants, milk fat can be hydrolysed by gastric lipase to some extent as in an infant’s stomach PH is close to neutrality.

• Digestion of fats in the small intestine:- In the small intestine, acidic food comes from the stomach and gets mixed with three alkaline juices namely bile, pancreatic and intestinal juices.

• Role of Bile:- it contains bile salts namely sodium glycocholate & sodium taurocholate which emulsify the fats. The bile salts break down fat droplets into many small ones by reducing the surface tension of fat droplets, this process is called emulsification. It increases lipase action on fat.

• Role of Pancreatic juice:- Pancreatic lipase is the principal enzyme for the digestion of fats. It converts emulsified fats (Triglycerides) into diglycerides and then into monoglycerides and finally, monoglycerides are converted into one fatty acid and one glycerol. 

• Role of Intestinal juice:- Intestinal juice also contains intestinal Lipases which hydrolyses some triglycerides, diglycerides and monoglycerides into fatty acids and glycerol like that of pancreatic lipase. Only a small amount of fats is digested in the lumen (cavity) of the small intestine & most of the intestinal digestion of fats occurs in the epithelial cells of the small intestine.