Enzyme Function
D. Crowley, 2007
Monday, July 31, 2017
Enzyme Function

To know what can affect how well an enzyme works
Absorption

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Digested food molecules are absorbed through the small intestine
(into our blood)
Once in the blood, the digested food molecules are carried around
the body, to where they are needed
Only small, soluble molecules can pass through the wall of the small
intestine
Villi

The inside wall of the small intestine needs to be thin, with a really
big surface area

This allows absorption to happen quickly and efficiently (so we
absorb as much food as possible)

To get a big surface area, the inside wall of the small intestine is
lined with tiny villi (one of them is called a villus)

These stick out and give a big
surface area. They also contain
blood capillaries to carry away
the absorbed food molecules.
Enzyme Function

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Enzymes only break down one type of food – e.g. lipase only
breaks down fat (lipids); amylase only breaks down
carboydrates; protease only breaks down protein
The rate at which enzymes break food down can be affected
by two main factors: – pH
– Temperature


What do you think the optimum temperature if for enzymes in
the body?
What about pH?
Experiment

Trypsin is an enzyme which breaks down protein

If Trypsin is added to milk it will break down the milk, turning
it from cloudy to translucent

You need to carry out an experiment to find out how the
temperature of the Tryspin affects how quickly the milk is
broken down
– You will have 3 boiling tubes of milk
– To each you will add some Tryspin which is at different
temperatures
– You need to time how long the solution went from being
cloudy to translucent
Procedure


Take 3 boiling tubes, and fill them each with 10ml of milk –
place them in a rack
Add 10ml of cold Trypsin to one boiling tube with milk in, and
begin the timer – time how long it takes for the solution to
become transparent

Repeat this with the second boiling tube, but this time add
10ml warm Trypsin

Repeat this with the third boiling tube, but this time add 10ml
boiling Trypsin

Record all your results
Explanation
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
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Explain why when the Trypsin was cold the solution turned
clear slowly
Explain why when the Trypsin was warm the solution turned
clear quickly
Explain why boiling the Trypsin caused the solution to remain
cloudy
Temperature
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This experiment shows that enzymes work best at a given
different
If it is too cold the enzyme takes a long time to break the food
molecules down
But if it is too hot the enzyme may not function at all – it has
been denatured
Enzymes in the human body usually denature above 45oC