Question

1. Where does proteins, lipids and carbohydrates get initially and finally digested?

2. Does more substrate concentration increase enzyme activity and if yes does it mean that the highest enzyme activity will be digested first?

Answer 1

1. Protein digestion begins in stomach with the action of pepsin enzyme When pepsin acts on the protein molecule of body,it first breaks the protein molecule bond that held it together ,is called peptide bonds.when these bonds get broken ,it create a chain of amino acids known as polypeptides.further these polypeptides move to small intestine where further digestion completed by pancreatic enzymes called trypsin.And finally digestion complete in small intestine.

Lipids - Most of the lipids that we consume are fats.digestion initially getting started from mouth in some and the stomach,but most of the digestion take place in small intestine.Bile produced by liver emulsifies fat globules into smaller .

Carbohydrates - carbohydrates digestion starts from mouth,where process of chewing mechanically breaks food into small pieces.enzymes in saliva initiate chemical digestion.and from there finally carbohydrate move to small intestine where pancreatic enzymes break them into simpler forms to be absorbed in blood stream.

2. Increasing substrate concenteration increases the rate of reaction because more substrate molecules will be colliding with enzyme molecules due to high number of activation sites,so more product will be formed.However, after a certain concenteration saturation occurs and any increase will not have affect on the rate of reaction.Since, substrate concenteration will no longer be limiting factor.The enzymes will effectively become saturated and will be working at their maximum possible rate.and it means highest enzyme activity will be digested first.