- Created by: Danni
- Created on: 10-04-12 15:07
Breakdown of food
When eating food, the mechanical way we break up the food is by chewing. The chemical way is the saliva.
The salivary glands produce an enzyme called amylase in the saliva to start the breakdoen of starch.
The liver is where the bile is produced.
The small intestine produced enzymes and absorbs food into the blood. It is covered in villi to increase the surface area.
The large intestine is where excess water is absorbed from the food.
The pancreas produces amylase, lipase and protease enzymes.
The stomach pummels the food with its muscular walls. It produces protease enzymes and hydrochloric acid ehich kills baceria and gives the right PH for the protease enzymes to work.
5 proporties of enzymes - They are spacific to their jobs (Amylaise only breaks down starch), they are protin molecules, they are fussy about their environment, they are spacific to PH/temperatures, the higher the temperature the faster the reactions.
When an enzyme denatures or changes shape, (this happens when the temperature is too hot/cold) they do not work, as the substance and the enzyme fit together like a lock and key but when the enzyme works too fast it denatures and the substance does not fit so it cant break down the substance.
Enzymes speed up the rate of chemical reactions. Enzymes are spacific because they only work on one substrate.The substrate fits onto the active site on the surface of enzymes. With an increase in temperature the rate of the reaction increases but eventually a temperature is reached which denatures the enzyme
Bile is produced in the liver. It is stored in the gall bladder before its released into the small intestine .
The hydrochloric acid in the stomach makes the PH too acidic for enzymes in the small intestine to work properly. Bile is alkaline so it neutralises the acid and makes the conditions more alkaline. This is because the enzymes in the small intestine work best in alkaline conditions.
It emulsifies fats. In other words it breaks the fat into tiny lipase. This gives a much bigger surface area of fat for the enzyme droplets to work on.