Name the variables which could be changed in the amylase/starch experiment.
To investigate the effect of: temperature - put the test tubes into water baths at a range of temperatiures; pH - use a range of different pH buffers; substrate concentration - vary the initial concentrations of the starch solutions
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Temperature - what does changing the temperature do?
The rate of an enzyme-catalysed reaction.
2 of 10
Temperature - Why does a higher temperature increase the rate of a reaction (at first)?
As more heat means the enzymes and the substrate particles have more energy. They move about more, so they're more likely to meet up and react.
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Temperature - What happens if the temperature gets too hot?
Some of the bonds holding the enzyme together break. This makes the enzyme lose its shape. Its active site doesn't fit the shape of the substrate any more, so it can't catalyse the reaction and the reaction stops.
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Temperature - What does this mean for the enzyme?
That it is denatured - it won't go back to its normal shape again if things cool down again.
5 of 10
Temperature - What does each enzyme have and when?
Its own optimum temperature when the reaction goes fastest. This is the temperature just before it gets too hot and starts to denature.
6 of 10
pH - What happens if it's too high or low and what does it lead to?
It interferes with the bonds holding the enzyme together. This changes the shape of the active sites and denatures the enzyme.
7 of 10
pH - What's often enzymes optimum pH?
Neutral pH 7. But, some work better in other pH's.
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Substrate Concentration - What affect does it have?
The higher the substrate concentration, the faster the reaction - it's more likely the enzyme will meet up and react with a substrate molecule.
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Substrate Concentration - What happens when there are too many substrate molecules?
The enzymes have about as much as they can cope with, as all the active sites are full, and adding more makes no difference.
10 of 10
Other cards in this set
Card 2
Front
Temperature - what does changing the temperature do?
Back
The rate of an enzyme-catalysed reaction.
Card 3
Front
Temperature - Why does a higher temperature increase the rate of a reaction (at first)?
Back
Card 4
Front
Temperature - What happens if the temperature gets too hot?
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