Unit 1 KA6 - Metabolic Pathways
What are Metabolic Pathways?
They are integrated and controlled pathways of enzyme catalysed reactions in cells.
What can metabolic pathways have?
Reversible steps, irreversable steps and alternative routes
Reactions within metabolic pathways can be...
anabolic and catabolic
What are anabolic reactions?
anabolic reactions build up large molecules from small molecules and require energy.
What are catabolic reactions?
Catabolic reactiosn break down large molecules into smaller molecules and release energy.
How are metabolic pathways controlled?
By the prescence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes
... is the energy required to break bonds within reactant molecules to iniate the reaction
Activation energy
As energy is absorbed, bonds become more and more unstable until the molecule is in a...
transition state
What will drive a sequence of reactions in a particular direction?
The presence of a substrate or the removal of a product
What are the 3 types of inhibition?
Competitve, non competitve, feedback
What do competitve inhibitors prevent?
substrate binding
Presence of a competitve inhibitor reduces the capacity of the enzyme to bind to substrate and so...
reduces rate of reaction.
What does increasing substrate concentration do?
reverses competitve inhibition
What do non competitve inhibitors bind to?
part of the enzyme other than the active site
Non competitve inhibitors change...
the shape of the active site
Increasing concentration of substrate...
does not reverse effect
When does feedback inhibition occur?
when the end product in the metabolic pathway reaches a critical concentration.
What happens with the end product during feedback inhibition?
It inhibits an earlier enzyme, blocking the pathway and preventing further synthesis of the end product