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11981334
Enzyme Action
Description
A2 Biology (Section 1) Mind Map on Enzyme Action, created by Dominic Weston on 24/01/2018.
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biology
section 1
a2
Mind Map by
Dominic Weston
, updated more than 1 year ago
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Dominic Weston
over 6 years ago
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Resource summary
Enzyme Action
Enzymes
Work intracellular, in the cell, and extracellular, outside the cell
Lock and Key model
substrate fits the active site like a key in a lock
however its found that the enzyme substrate complex changed shape slightly
'Induced fit' a better theory
substrate has to make the active site change its shape to fit specifically for the substrate
Properties of enzymes structure
Related to tertiary strcuture
active site due to tertiary which itself is due to primary
Each enzyme different
Mutations of gene may change enzyme produced
very specific, catalyses one reaction
as one complementary substrate fits
Factors Affecting Enzymes
Temperature rises, causing molecules to vibrate more
if temperature goes too high,
Breaks some bonds within the enzyme so it loses shape
Enzyme becomes denatured, loses function as an enzyme
pH, most enzymes optimum at 7 pH
Exceptions e.g. pepsin at pH 2
ionic and H-bonds in tertiary structure can be altered by acids and akalis
denatures enzymes
Concentrations
Increasing Enzyme Conc
Increases the frequency of successful collisions to form substrate-enzyme complexes
This increases the rate of reaction
Up to a point that the substrate runs out if substrate limited
Increases the rate up to the point of "saturation"
Saturation is when all the active sites are full
Therefore adding more substrate makes no difference
Conc of substrate does decrease over time as products formed
Rate also decreases if substrate is not added, initial rate is the highest
Increasing Substrate Conc
Inhibition
Eznyme inhibitors prevent enzyme activity
Molecules bind to enzyme to inhibit it
Competitive
Competitive inhibitors have similar shape to substrate
Inihibtors and substrate compete to occupy active site
If inhibitors occupy the active site no reaction takes place and the active site is blocked
If there is high substrate conc, more chance for substrate to bind to active site
Increases rate of reaction to a point
Increase Inhibitor conc
Inhibitors will occupy nearly all active sites leaving a very low rate of reaction
Non-competitive
Non-competitive inhibitor attach to binding sites, way from the active site
Causes active site to change shape
Substrate can no longer bind to active site
Prevents enzyme from functioning
Changing conc of substrate has no effect
Enzyme Reactions
Measuring the rate of enzyme-controlled reactions
Measure how fast product is made
Catalase breaks down hydrogen peroxide to form water and oxygen
Measure how much oxygen produced
Measure how fast substrate is broken down
Biological Catalysts
Catalysts for metabolic reactions
Lower the Activation Energy of a Reaction
If substrates are closer together, reduces repulsion easier to bond molecules together
If breaking down molecule, attatching to active site puts pressure on molecules bonds
Have active sites and specific shape
Proteins
Highly specific due to tertiary structure
Active site have complementary shape of substrate
When substrate and enzyme react, substrate-enzyme formed
Media attachments
Enzyme Inhibition (binary/octet-stream)
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