A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
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What molecule is changed in the reaction?
The substrate
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What is the active site?
Where it joins on to its substrate to catalyse the reaction
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What affects the rate of reaction?
Temperature, pH and Substrate concentration
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What happens if the temperature is too high?
Some bonds holding the enzyme breaks.
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What happens if some bonds break?
It changes the active site, so teh substrate won't fit. this is called denatured
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What pH is best for the reactions?
Often pH 7 (neutral) BUT NOT ALWAYS
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What pH is best for pepsin (an enzyme which breaks down proteins in the stomach)?
pH 2
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Explain why enzymes have an optimum pH?
If the pH is too high or too low it can interfer with th ebonds holding the enzyme together. This changes the shape of the active site and denature the enzyme.
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What is step 1 to investigating the affect of pH on enzyme activity?
Put a drop of iodine solution into every well of a spotting tile.
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What is step 2 to investigating the affect of pH on enzyme activity?
Using a tripod, heat-proof mat and guaze, put a beaker of water on top of the tripod and heat the water to 35C
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What is step 3 to investigating the affect of pH on enzyme activity?
Use a syringe to add 3 cm3 of amylase solution and 1 cm3 of buffer solution to a test tube. using test tuber holder place the test tubes in the beaker for 5 minutes.
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What is step 4 to investigating the affect of pH on enzyme activity?
use a different syringe to add 3 cm3 of a starch
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What is step 5 to investigating the affect of pH on enzyme activity?
immediatly mix the contents of the boiling tube and start a stop clock
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What is step 6 to investigating the affect of pH on enzyme activity?
Use continuous sampling to record how long it takes for the amylase to break down. to do this use a dropping pipette to take a fresh sample from the boiling tube every 10 seconds. put a drop into every well.
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What is step 7 to investigating the affect of pH on enzyme activity?
Repea the experiment with buffer solution of different pH valyes.
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What is step 8 to investigating the affect of pH on enzyme activity?
Remember to control variables each time.
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What colour will the iodine solution stay if there is no starch present?
Browny-orange
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What is the equation to work out the Rate of reaction?
Rate = 1000/time
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An enzyme-controlled reaction was carried out pH 4. After 60 seconds 33 cm3 of product has been released. calculate the rate of reaction in cm3 s-1
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