Digestion Definition

Digestion is defined as the process of breaking down large, insoluble molecules of food into smaller, water-soluble molecules which can then be readily absorbed by the body

Digestion is one among many life processes observed in nearly all living organisms. The process involves breaking down complex molecules into simpler molecules that can be readily absorbed by the body. In higher organisms such as humans, a “tube” exists for the purpose of digestion. Once the food molecules are broken down into simple molecules, they are absorbed into the blood plasma.

Other organisms, such as amoeba exhibit another form of digestion called phagocytosis. Here, the organism, usually a single-celled organism, uses its plasma membrane to engulf food particles, consequently giving rise to an internal component. Once inside, the food particles are broken down and absorbed. Some animals also exhibit unusual feeding behaviour due to shortcomings of their digestive system.

Animals such as hydra have only one opening in their digestive canal. Therefore they ingest food, digest it and egest it through the same opening. Higher animals have two openings in their digestive canal thus enabling continuous feeding.

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Frequently Asked Questions on Digestion


Define Digestion.

Digestion is the process of breaking down complex, insoluble molecules of food into smaller, simpler molecules which can then be readily absorbed by the body


What is phagocytosis?

This type of digestion is seen in unicellular organisms such as amoeba, where the organism’s cell membrane is used to surround and engulf the food particle and transfer it inside the cell for digestion.


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