1.8 Factors affecting enzyme action

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  • Created by: Dane
  • Created on: 02-03-20 11:44
For an enzyme to work what two things must happen
1. It must come into contact with its substrate 2. It must have an active site which fits the substrate
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When an enzyme catalysed reaction runs its time course what two changes are most frequently measured
1. The formation of the products of the reaction 2. The disappearence of the substrate
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How do we measure the rate of reaction at any point of a reaction
By measuring the gradient
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When investigating the effect of a named variable on the rate of a enzyme reaction what conditions must be put into place
All other variables must be kept constant e.g. If measuring the effect of temperature then PH, enzyme concentration, and substrate concentration must be kept constant
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What is meant by the term complimentary
This is used to denote that the active site and the substrate are not the same, they are complimentary
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What happens when you increase the temperature of a reaction
This increases the kinetic energy of a reaction as a result enzymes move around more rapidly and collide with each other more often
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At what temperature does the enzymes active site begin to change shape
45 degrees celcius
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At what temperature does the enzyme become denatured
60 degrees celcius
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What is the optimum temperature of many enzymes in the body
40 degrees celcius
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Why is the normal body temperature of birds around 40 degrees celcius
This is because they have a high metabolic rate for the energy required for flight
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What is meant by the PH of a solution
The concentration of hydrogen ions
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What formula is used to calculate the PH of a solution
-log10[H+] therefore a hydrogen ion concentration of 1 x 10^-9 has a PH of 9
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How does the PH affect how an enzyme works
The PH alters the charges on the amino acids that makes up the active site of an enzyme if it is too much it may cause the enzyme-substrate complex to be compromised
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Secondly
A significant change in PH may cause the bonds maintaining the enzymes tertiary structure to break changing the shape of the active site
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Why are PH fluctuation in an organism usually unlikely to denature it
Because they are usually small
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Why can enzymes work efficiently at very low concentrations
Once the enzyme-substarte complex has been formed it is free to repeat the procedure on another substrate, this means the enzymes are not being used up during the process
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Why does the graph of the rate of reaction against enzyme concentration show a prortionate increase
This is because there are more substrates than the enzymes active site can cope with
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What happens when the substrate is limiting
The any increase in the enzyme concentration with have no effect on the rate of reaction
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Why does the graph level off at this point
Because the avalible substrate is already being used by the existing enzyme molecules
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What is a inhibitor
They indirectly or directly interfere with the functioning of the active site of an enzyme in order to reduce its activity
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What is a competitive inhibitor
They bind to the active site of a enzyme
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What is a non competitive inhibitor
They bind to the enzyme at a position other than the active site
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What determines the effect of the enzyme activity
The difference between the concentration of the inhibitor and the concentration of the substrate
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What are two examples of competive inhibitors
1. the inhibition of succinate by the inhibitor malonate 2. The inhibition of the enzyme transpeptidase by penicillin
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Why does the increase of the substrate concentration no decrease the effect of the inhibitor
The substrate and the enzyme are not competing for the active site
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Other cards in this set

Card 2

Front

When an enzyme catalysed reaction runs its time course what two changes are most frequently measured

Back

1. The formation of the products of the reaction 2. The disappearence of the substrate

Card 3

Front

How do we measure the rate of reaction at any point of a reaction

Back

Preview of the front of card 3

Card 4

Front

When investigating the effect of a named variable on the rate of a enzyme reaction what conditions must be put into place

Back

Preview of the front of card 4

Card 5

Front

What is meant by the term complimentary

Back

Preview of the front of card 5
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