6.4 Food Digestion


6.4 Food Digestion

1.      Digestion is the process that breaks down complex food substances into simpler, soluble molecules that are small enough for the body to absorb.
2.      Digestion breaks down
     (a) carbohydrates into glucose molecules,
     (b) proteins into amino acids, and
     (c) lipids into glycerol and fatty acids.
3.      Digestion involves both physical and chemical processes.
4.      Physical digestion
     (a) involves the breaking of large pieces of food into smaller pieces by chewing action of the teeth.
     (b) this action increases the surface area of the food particles for enzyme reaction.
5.      Chemical digestion
      Digestive enzymes break down of large complex food particles into simple soluble molecules by specific digestive enzymes in the presence of water. The process called hydrolysis.