y7 life 10 digestive enzymes

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Digestive Enzymes

Learning Objective:

• Explain the role of enzymes in digestion.

Starter:

• Name the organs of the digestive system in order.

Can you remember the names of all the parts of the digestive system?

Mouth

Oesophagus

Stomach

Small Intestine

Large Intestine

Rectum

Enzymes

Different enzymes are added by the digestive system at various stages.

There are different enzymes for different functions.

Let’s look at the different enzymes which breakdown food

How do enzymes work?

AmylaseAmylaseAmylaseAmylase

Amyase

Carbohydrates are chains of identical sugar molecules.

The digestive enzymes called carbohydrases break the chemical bonds between the individual sugar molecules in each carbohydrate chain.

carbohydrase

long carbohydrate

moleculesugar

molecules

Enzymes and carbohydrate digestion

Investigation

1. Tie one end of visking tubing, fill with starch & amylase solution.

2. Soak in warm water for 15-20 minutes.

3. Test the water for glucose using Benedict’s solution.

Practical Activity

Safety First: Wear safety

goggles Stand up Tuck your chair &

bags under your desk

Tie back long hair

ProteaseProteaseProteaseProtease

Proteins are made up of amino acids. There are 20 different types of amino acids.

Proteins are digested by digestive enzymes called proteases. These enzymes work in an acidic environment to break proteins into smaller amino acids.

protease

long protein molecule

amino acid molecules

Enzymes and protein digestion

LipaseLipaseLipaseLipase

Fats are digested in two stages:

Firstly, bile (released by the gall bladder) allows the fat to “mix” with water by breaking the fat into smaller droplets. This is called emulsification.

Secondly, the digestive enzyme lipase breaks each fat molecule into the smaller glycerol fatty acid molecules .

bile

lipase +

fat molecule glycerol fatty acids

Enzymes and fat digestion

Digestive EnzymesDigestive EnzymesDigestive EnzymesDigestive Enzymes

Digestive Enzymes

Blue Benedict’s solution turns orangey-red when it is boiled with glucose.

blue turns orange/red= glucose

heat

chopped up food

hot water

Digestive enzymes activity

Digestive Enzymes

Learning Objective:

• Explain the role of enzymes in digestion.

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