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26 Cards in this Set
- Front
- Back
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A metabolic pathway that breaks down complex molecules to simpler ones releasing energy |
Catabolic |
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A metabolic pathway that builds up complex molecules from simpler ones using energy |
Anabolic |
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What is activation energy? |
The energy needed to break chemical bonds in reactant chemicals |
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What is an enzyme? |
A protein molecule that catalyses a chemical reaction |
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Identify three properties of an enzyme |
They lower activation energy They speed up reactions They remain unchanged at the end of a reaction |
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How do enzymes lower activation energy? |
The active site ensures that reactants are held closely together in the correct orientation for a reaction to occur |
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Where on an enzyme molecule does the reaction take place? |
Active site |
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What does the term 'induced fit' mean? |
The enzyme active site moulds itself round the substrate ensuring a reaction. |
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Name 3 factors that affect enzyme activity |
Temperature pH Substrate concentration |
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What happens to enzyme activity with increasing substrate concentration? |
As substrate concentration increases enzyme activity increases till it plateaus as the no of active sites available is limiting. |
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What 3 genes can be found on an operon? |
Regulator gene Operator gene Structural gene |
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What is the function of a regulator gene? |
This gene codes for a repressor protein |
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What is the function of a repressor protein? |
It binds to the operator gene. |
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What effect does the binding of the repressor protein on the operator gene have? |
It causes the operator gene to turn off the structural gene. |
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What is the function of the structural gene? |
To code for the enzyme in the metabolic pathway e.g. Lactose/Galactose |
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What molecule can bind to the repressor molecule and prevent it from bonding to the operator gene? |
The inducer |
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What is another term for the inducer (a molecule that when present a gene becomes switched on to) |
Signal molecule |
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What are the two types of enzyme inhibitor? |
Competitive and non competitive |
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Which type of inhibitor has a similar shape to the enzymes substrate and bonds to the active site? |
Competitive |
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What is the effect of a competitive inhibitor on he rate of an enzyme catalyses reaction? |
It slows the reaction down |
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How can the effect of a competitive inhibitor be overcome? |
Increasing the substrate concentration |
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What effect does a non competitive inhibitor have on the rate of an enzyme catalysed reaction? |
The reaction rate is lowered as the number of active enzymes is reduced. |
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What type of inhibitor changes the shape of an enzymes active site? |
Non competitive |
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What is the name for the site on an enzyme to which a non competitive inhibitor binds? |
Allosteric site |
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What is an activator? |
A regulatory molecule that can bind to an enzymes allosteric site and activate an enzyme. |
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What do we call the build up of an end product in a metabolic pathway that binds to and inhibits an enzyme at the beginning of a metabolic pathway? |
End product inhibition |
