enzymes Flashcards
what are enzymes
globular proteins used in metabolic reations. they are catalysts (speed up biological reactions)
definition of metabolism
all reactions of the body
what are the 2 types of metabolism
- anabolic
- catabolic
anabolic metabolism
building up of molecules e.g. protein synthesis (condensation)
catabolic metabolism
breaking down molecules e.g. digestion (hydrolisis)
enzyme substrate complex
a temporary complex formed when an enzyme binds to its substrate molescules
competitive inhibitor
A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics
non competitive inhibitor
a substance that reduces the activity of an enzyme by entering a site away from the active site, thus changing the shape of the active site
factors that effect enzyme function
- Enzyme Concentration,
- Substrate Concentration,
- Temperature,
- pH
lock and key model
The model of the enzyme that shows the substrate fitting perfectly into the active site
induced fit model
The model of the enzyme that shows the substrate binding to the active site and the active site altering slightly
collision theory
for an enzyme to catalyse a reaction it must…
* come into contact with a substrate
* substrate must be complimentary to active site
* must collide with enough energy
activation energy
the minimum amount of energy required to activate a reaction
exergonic reaction
energy released
endergonic reaction
energy absorbed
what are enzyme inhibitors
substances that directly or indirectly interfere with the functioning of the active site of a specific enzyme so decrease the rate of reaction
what do enzyme inhibitors cause
- lower frequency of successful collisions
- lower number of enzyme substrate complexes forms
- lower number of reactions taking place
what are the types of inhibitors
- competitive
- con-competitive
competitive inhibitors structures and functions
- have similar shape to substrate allowing them to bind to & occupy the active site of the enzyme
- they compete with substrates for the active site
- the binding of competitive inhibiter is not perminent
non-competive inhibitor structure and function
- attach to enzyme at a site that is not the active site (allosteric site)
- binding of inhibitor causes a change in the tertiary structure- changing active site (no longer complimentary)
