Question

What are some examples of chemical digestion?

Answer 1

Chemical digestion is a process that is enzyme-mediated breakdown of larger molecules into smaller molecules and their monomers. It takes place in the gastrointestinal tract. It can only be achieved by the presence of many enzymes that are present in different parts of the body.

Complete answer:
Food is taken by organisms into the food vacuole or alimentary canal. It is in the body after it enters the cytoplasm or the blood and lymph by passage through the membrane of the food vacuole or the mucous membrane of the alimentary canal. The breakdown of large, complex, insoluble molecules in the ingestion food into small, simple, soluble molecules fit for absorption is called digestion.

Food is digestion in the body in two ways: chemical and mechanical. Chemical method involves breakdown by the action of chemical agents like enzymes, acids and bile.

STOMACH ACIDS- It contains gastric glands that release acid in the stomach to create an acidic medium. The low pH level helps in denaturation of proteins and other macromolecules into small molecules. The epithelium contains mucous membrane that prevents the acids from damaging the gastric lining of the stomach.
BILE- It is secreted and produced by the liver and is stored in gallbladder prior to release into the intestine. It contains bile salts (bilirubin and bili- verdin) and interacts with fat globules and divides them into small molecules.
ENZYMES- They are the biological catalysts that help to speed up the chemical reaction by lowering the activation energy. They allow the digestion process to therefore occur at body temperature and at sufficient spends for survival requirements. The types of enzymes secreted and dependent on macromolecules that are needed for hydrolysis.

EXAMPLES:
- Carbohydrates digestion takes place in the mouth on release of amylase from salivary glands and ends up in the small intestine. Enzymes for disaccharide hydrolysis are immobilized on the epithelial lining of the small intestine.
- Protein digestion takes place in the stomach with the release of proteases and it can function in acidic pH (=2). Small polypeptide chains that enter the small intestine break down and are later released into the pancreas.
- Lipids breakdown takes place in the intestine firstly with the emulsification of fat globules by release of bile from gallbladder. Large fat droplets are then digested by the lipases.
- Nucleic acids are digested by nucleases released by the pancreases into small nucleosides.

Note: Food is defined as any substance which, when taken, digested, and absorbed into the body, provides material for growth, maintenance, and repair, and also furnishes energy for life activities. It is digested into the body in various parts of the body by the enzymes present in them for taking up nutrients and using them for the source of energy.