1.7 Enzyme Activity Flashcards
What are enzymes
Globular protiencs that act as a catalyst they alter the rate of chemical reaction whithor undergoing permanent changes themselves
What conditions must be satisfied so a reaction to take place
The molecules must collide with sufficient energy to alter the arrangement of their atoms
The free energy of products must be less than the substrates
Many reactions require initial energy to start the activation energy
What is the active site and how is it formed
It is the functional site and is made up of small number of amino acids it forms a small depression within the enzyme
What is a substrate
The enzyme acts on this it fits neatly into the depression and held by bonds between certain amino acids on active site and groups on the substrate molecule
What is the indices for model
Active site forms as substrate is close proximity to the enzyme or alter it shape to it can mould itself around the substrate it has a general shape but changes in the presence of the substrate as it changes shape the enzyme puts a strain on the substrates which distorts the bonds in the substrate which lowers energy required to break bond
How will an enzyme work two ways
Come into physical contact with its substrate
Have an active site that fits the substrate
How to measure the enzyme catalyst reaction
Formation of products
Or disappearance of substrate
Explain in general the graph shape in enzyme catalyst graph
There is a lot of substrate but no products
It’s very easy for the substrate and enzymes to interact
The enzymes sites are filled and the substrate is broken down into its products
The amount of substrate decreases as more products are made
This makes it difficult for substrate to come into contact with the enzyme molecules so rats of reactions started to decrease
Rate of reaction starts to slow until there is little substrate left to react
What does a rose in temp do to enzyme activity why
Increase the kinetic energy the molecules move around more rapidly and collide with each other more this means the enzyme and substrate collide lead to enzyme substrate complexes formed more leads to more product formation so rate of reaction increase
What if the temperature is too high
Denaturationoxcurs permanent damage to the enzyme enzyme doesn’t function again it causes the hydrogen bonds to vibrate and break or distort enzyme loses shape so substrate can no longer form a complex so no reaction
What does ph change do to an enzyme
A change in ph alters the charge on amino acids that make up the active site as a result the substrate can no longer bind to active site so complex cannot form
Depending on significance of alteration of charge it may cause the bonds in remaining enzyme maintaining tertairy structure to breakdown active site shape also changes too
What is arrangement of active site dependent on and why might ph change affect this
Partially determined by hydrogen and ionic bonds between nh2 and cool the change in h+ ions affect this bonding causing active site to change shape
How does rate of reaction increase with enzyme concentration
Too few enzyme molecules to allow all substrate molecules to find an active site at one time the rate of reaction is only half the max possible number
When increase off enzyme molecules all the substrate molecules acan occupy an active site at one time the rate of reaction has doubled to its max as all active sites are filled
The addition of further enzyme molecules has no effect as there are already enough active sites to accommodate all the present substrate molecules
How does substrate concentration effect rate of reaction
There are too few substrates to occupy all active sites so rate of reaction is only at its half with all enzyme molecules present
Whith substrate molecules doubled there are double number of active sites occupied at one time rate of reaction has doubled
Addison of further substrate has no effect as all active sites are already full
