enzymes structure and purpose
TRANSCRIPT
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7/27/2019 Enzymes Structure and Purpose
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Enzymes
We couldnt live with out them!
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7/27/2019 Enzymes Structure and Purpose
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What is an enzyme?
Known as a BIOLOGICAL CATALYST
Catalyst is something that speeds up a
chemical reaction
Biological catalyst speeds up reactions in
living cells
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Activation Energy
Do this by lowering the ACTIVATIONENERGY - the energy required for areaction to begin
Progress of reaction
E
nergy
Uncatalysed reaction
Catalysed reaction
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Properties of Enzymes
They are made ofPROTEIN
They are not changed by the reactions
they speed up They are SPECIFIC- means that only one
particular enzyme will work with one
particular substrate
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Other terms you need to know
Substrate the substance that the
enzyme works on e.g.Amylase the
substrate is starch
Product the substance that is made by
the reaction e.g. Breakdown of starch by
Amylase the product is Maltose
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CATALASE
Found in animal and plant cells
Needed to speed up the breakdown of
HYDROGEN PEROXIDE
Breaks it down to OXYGEN and WATER
The word equation for this looks like this
HYDROGEN PEROXIDE
CATALASE
OXYGEN AND WATER
HPCOW
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Amylase
Found in saliva and in the pancreas
Break down enzyme
Breaks STARCH down to MALTOSE
Word equation looks like this
STARCH MALTOSE
AMYLASESAM
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Potato Phosphorylase
Synthesis enzyme (builds up)
Builds Glucose-1-Phosphate moleculesinto Starch
The formation of starch is tested usingiodine solution
Phosphorylase
G1PPS
Glucose-1-Phosphate Starch
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More about Specific
This means amylase will only breakdownstarch
Catalase will only breakdown hydrogen
peroxide
Amylase will NOT breakdown hydrogen
peroxide
Catalase will NOT breakdown starch
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Lock and Key
All enzymes have a special shaped areathat fits onto their substrate
This area is called the ACTIVE SITE
This Active site will fit onto the substrate
while the reaction takes place
Because it fits like a lock and key we call
this the lock and key mechanism
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Model of Lock and Key
productssubstrate
enzyme enzyme unchangedactive site
enzyme substrate complex
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Effect of Temperature
Speed of reaction increases until anOptimum temperature is reached
Optimum temperature is the temperature
at which the enzyme works best
After this point the rate of reaction
decreases until there is no reaction At this point enzyme is said to be
DENATURED active site destroyed
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Effect of pH
Most enzymes have an optimum pH of 7
Some enzymes have a different optimum
pH for example pepsin has an optimum pHof 2