1. Starter:Main Organs of the Digestive System
Click on this LINK to see a simulation of some body organs.
Drag each organ to its correct position in the human body.

2. Enzymes Learning Objectives: Know what “enzymes” are.
Know how the structure of an enzyme helps it to work in aiding the digestion of food.
Be able to give the names of enzymes used in digestion and what food substances are broken with the help of each enzyme.

3. What are Enzymes Click on this LINK to see an animation of an enzyme.
You only need to study the top animation.
Write in your notebook a sentence or two on how you think this animation is linked to the function of the human digestive system.

4. Enzymes and their structure+ + ↔ ↔
enzyme
reactant +
enzyme-reactant complex ↔
products
Enzymes are biological catalysts – they speed up reactions in living things.
Enzymes are protein molecules made up of long chains of amino acids.
These long chains are folded to produce a special shape enabling other molecules (substrate) to fit into the enzyme (active site).

5. Factors affecting enzyme action
denatured
normal
heat pH
The shape of the enzyme is vital to its function.
The main factors affecting enzyme action are 1.) temperature and 2.) pH
1.) High temperatures can destroy the enzymes ‘special shape’ so it becomes denatured.
2.) Different enzymes work best at different pH values.

6. Enzymes in Digestion Enzyme: Amylase Protease Lipase Produced in:
- Salivary glands
- Pancreas
- Small intestine
Stomach
Pancreas
Small intestine
Job:
Catalyses the breakdown of starch into sugars
Catalyses the breakdown of proteins into amino acids
Catalyses the breakdown of lipids (fats and oils) into fatty acids and glycerol
Where:
- Mouth
Also:
1.) The stomach produces hydrochloric acid.
Enzymes in the stomach work best in acidic conditions
2.) The liver produces bile which is stored in the gall
bladder before being released into the small intestine.
Bile neutralises the acid that was added to food in the
stomach. This provides alkaline conditions in which
enzymes in the small intestine work best at.

7. Plenary: Enzymes & Digestion