Digestion

What is Digestion?

Digestion is when large polymer molecules are broken down into their monomer molecules.
- Proteins (polymers) are broken down into amino acids (monomers)
- Lipids (polymers) are broken down into fatt
- y acids and glycerol (monomers)
- Carbohydrates (polymers) are broken down into glucose (monomers)
- Nucleic acid (polymer) is broken down into nucleotides (monomers)
Digestion is also an EXTRACELLULAR PROCESS which means that it occurs in the gut (a tube that runs from the mouth to the anus) with help from enzymes and processes like osmosis, diffusion, and passive transport.
Digestion occurs with help from hormones which help to coordinate different organs to work together to allow this phenomenon to occur.
Digestion is also known as the physical and chemical breakdown of large food particles into smaller molecules that can move through cells and enter our internal (cell) environments.

Physical digestion is the mechanical breaking down of food molecules.
It occurs in the mouth through the process of chewing, stomach through the process of churning and the small intestine through the process of fat breakdown or emulsification.
Physical digestion functions to increase the SURFACE AREA of food so chemical digestion can occur at a more rapid rate.

Chemical digestion is when hydrolysis reactions (in the presence of water) break down large food molecules (polymers) into their monomers.
This occurs in the mouth when salivary amylase (enzyme) is released, stomach when pepsin enzyme is released and in the duodenum as a multitude of different enzymes are released.
The body functions to break polymers into the t monomers for metabolic needs
Food must be broken down during digestion to allow these nutrient molecules (monomers) to be absorbed into different body cells and distributed around the body. This process is known as ABSORPTION.
- Absorption is the passage of digestion nutrients from the gut lumen (a hollow tube in the small intestine) to the blood or lymph vessels that surround it. When nutriences gets into the blood or lymph it is able to be moved around the body.
Each organ system in the body has a unique function, pH, temperature and hydrolytic enzymes.
After this nutrient is absorbed into different cells around the body the process of ELIMINATION occurs which is the release of undigested residue from the body.