Chemical Digestion

Chemical digestion occurs through the action of digestive enzymes and other chemicals, enabling the body to absorb and utilize nutrients from the ingested food efficiently.

Large Insoluble Molecules are broken down into smaller, more soluble molecules

The human body cannot directly absorb large, complex molecules such as proteins, starches, and fats. These molecules need to be broken down into smaller, soluble forms to be absorbed through the lining of the digestive tract and into the bloodstream.

 Once broken down, these smaller soluble molecules can be transported to various cells and tissues, where they are used for energy production, growth, and other biological functions.

Functions of Enzymes in Chemical Digestion

Amylase 

• Breaks down starch to simple reducing sugars
• Secreted in the mouth (salivary amylase) and the pancreas (pancreatic amylase).

Amylase is an enzyme produced in the salivary glands and the pancreas. It is found in saliva and pancreatic juice.

Its primary function is to break down complex carbohydrates like starch into smaller, soluble sugars. Starch is a large polysaccharide composed of many glucose molecules linked together.

Salivary amylase is released in the mouth and begins breaking down starch into simpler sugars (e.g., maltose and dextrins) while chewing.

Pancreatic amylase is released into the small intestine and continues the digestion of starch into maltose and dextrins.

Amylase catalyzes the hydrolysis of the starch, breaking the glycosidic bonds between the glucose units, and converts it into simpler sugars like maltose and dextrins.

Proteases 

• Breaks down protein to amino acids
• They are produced in the stomach (pepsin) and pancreas (trypsin, chymotrypsin, and carboxypeptidase).

Proteases are enzymes responsible for breaking down proteins into their constituent amino acids.

Proteins are large, complex molecules composed of long chains of amino acids linked together by peptide bonds.

Proteases hydrolyze these peptide bonds, breaking the protein molecules into smaller peptides first and then into individual amino acids, which are small, soluble molecules.

Lipase 

• Breaks down fats and oils to fatty acids and glycerol
• Secreted in the pancreas and released into the small intestine.

Its primary role is to break down fats and oils, which are large lipid molecules composed of glycerol and three fatty acid chains.

Lipase catalyzes the hydrolysis of the ester bonds between the glycerol and fatty acids, resulting in the formation of fatty acids and glycerol. These are smaller, soluble molecules that can be easily absorbed through the intestinal lining.