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B2.4 Enzymes

4.1 Enzyme Structure
Enzymes are biological catalysts ­ they speed up reactions.

Enzymes are large proteins and each has a particular shape. This shape has an area where
other molecules can fit in. This area is called `active site'.

Too high a temperature will change the enzymes shape,…

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B2.4 Enzymes

4.2 Factors affecting Enzyme Action

Reactions take place faster when it is warmer. At the higher temperature the molecules move
around more quickly so collide with each other more often and with more energy.

However, if the temperature gets too hot the enzyme stops
working. That's because the…

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B2.4 Enzymes

4.3 Aerobic Respiration
The equation for respiration is:

Glucose + Oxygen Carbon Dioxide + Water [+Energy]
C6H12O6 + 6O2 6CO2 + 6H2O + energy

The process takes place in the mitochondria.

The energy released is used to:

Build larger molecules from smaller ones
Enable muscle contraction in animals…

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B2.4 Enzymes

4.4 Enzymes in Digestion
Digestion involves the breakdown of large, insoluble molecules into smaller soluble ones.

Amylase (a carbohydrase) is produced by the salivary glands, the pancreas and the
small intestine. Amylase catalyses the digestion of starch into sugars in the mouth and
small intestine.
Protease is produced…

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B2.4 Enzymes

4.5 Speeding up Digestion
Protease enzymes in the stomach work best in acid conditions. Glands in the stomach
wall produce hydrochloric acid to create very acidic conditions.
Amylase and lipase work in the small intestine. They work best when then conditions are
slightly alkaline.
The liver produces bile…

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B2.4 Enzymes

4.6 Making use of Enzymes
Biological washing powders contain enzymes that digest food stains. They work at lower
temperatures than ordinary washing powders so can save us money.

We can also use:

Protease enzymes to predigest proteins in some baby foods
Isomerases to convert glucose into fructose. Fructose…


lisa linsdell


Taken from the AQA revision guide, key words and terms highlighted. Useful key points to help summarize the information.



It was so great, I just wanted to bungee jump without the rope.



looool @SirSnazza

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