Explain the role of large intestine in digestion process.

1. Conversion of proteins into amino acids, fats to fatty acids and monoglycerides, nucleic acids to sugar and nitrogenous base and carbohydrates to monosaccharides marks the end of digestion of food.

2. Food is now called chyle. Chyle is an alkaline slurry which contains various nutrients ready for absorption. 

3. The nutrients are absorbed and undigested remains are transported to large intestine. 

4. Mucosa of large intestine produces mucus but no enzymes. 

5. Some carbohydrates and proteins do enter the large intestine. 

6. These are digested by the action of bacteria that live in the large intestine. 

7. Carbohydrates are fermented by bacterial action and hydrogen, carbon dioxide and methane gas are produced in colon. 

8. Protein digestion in large intestine ends up into production of substances like indole, skatole and H2S. 

9. These are the reason for the odour of faeces. These bacteria synthesize several vitamins like B vitamins and vitamin K.