JEE Main & Advanced Chemistry Biomolecules / जैव-अणु Digestion of food

Digestion is the process by which complex constituents of food are broken down into simple molecules by a number of enzymes in mouth, stomach and small intestine. The simple molecules thus formed are absorbed into blood stream and reach various organs.

Raw food may be taken as such or after cooking. It is chewed in the mouth and swallowed when it passes through a long passage in the body called alimentary canal. During this passage it gets mixed with various enzymes in different parts of the alimentary canal. The carbohydrates, proteins and fats are converted into simpler forms which are then carried by blood to different parts of the body for utilization. Digestion of food can be summarized in the following form

(1) \[\text{Polysaccharide}\underset{\left( \begin{smallmatrix} \text{Saliva (mouth);} \\ \text{Pancreatic juice} \\ \text{      (Intestine)} \end{smallmatrix} \right)}{\mathop{\xrightarrow{\text{Amylase}}}}\,\text{Disaccharides (maltose, etc}\text{.)}\underset{\text{(Intestine)}} {\mathop{\xrightarrow{\text{Maltase}}}}\,\text{Glucose}\]Disaccharides

\[\text{Disaccharides (maltose, etc}\text{.)}\underset{\text{(Intestine)}}{\mathop{\xrightarrow{\text{Maltase}}}}\,\text{Glucose}\]

(2)\[\text{Proteins}\underset{\text{(Stomach)}}{\mathop{\xrightarrow{\text{Pepsin/}HCl}}}\,\text{Proteases and Peptones}\underset{\left( \begin{smallmatrix} \text{Chemotrypsin} \\ \text{Pancreatic juice} \\ \text{   (Intestine)} \end{smallmatrix} \right)} {\mathop{\xrightarrow{\text{Trypsin}}}}\,\text{Peptides}\underset{\text{(Intestine)}}{\mathop{\xrightarrow{\text{Peptidases}}}}\,\text{Amino acids}\]

\[\text{Peptides}\underset{\text{(Intestine)}}{\mathop{\xrightarrow{\text{Peptidases}}}}\,\text{Amino acids}\]

(3) \[\text{Fats}\underset{\text{(From liver)}}{\mathop{\xrightarrow{\text{Bile salts}}}}\,\text{Emulsified fat}\underset{\left( \begin{smallmatrix}  \text{Pancreatic and} \\ \text{intestine juice} \end{smallmatrix} \right)}{\mathop{\xrightarrow{\text{Lipases}}}}\,\underset{\text{Glycerol}}{\mathop{\underset{+}{\mathop{\text{Fatty acids}}}\,}}\,\]