Unit 2 - Metabolic Pathways Flashcards
What is a metabolic pathway?
Metabolic pathways are integrated and controlled pathways of enzyme-catalysed reactions within a cell.
Anabolic pathways?
Synthesize LARGER molecules from SMALLER ones and release energy
Catabolic pathways?
Break down LARGER molecules down to SMALLER ones and release energy
What are metabolic pathway steps described as?
Reversible and irreversible
When does a metabolic pathway contain an alternative route?
When there is a plentiful supply of one metabolite in a pathway
How is the metabolic pathway driven?
Metabolic pathways are controlled by the presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes.
How do enzymes speed up chemical reactions?
By lowering the activation energy
How do enzymes function?
Enzymes have active sites with high AFFINITY for substrate molecules and when the 2 combine the reactions are orientated to active site = activation energy lowered and products released because lower AFFINITY for active site
What is an induced fit?
When the substrate enters the active site, it changes slightly making it fit the substrate molecule snugly.
What happens when substrate concentration is low?
There isn’t enough substrate molecules to make full use of all the active sites = reaction rate lowered
What happens when substrate concentration is high?
There is lots of substrate molecules to make full use of all active sites = reaction rate increased
*eventually further increase in concentration doesnt do anything as all active sites are already in use
What is the role of inhibitors in metabolic pathways?
Inhibitors control metabolic pathways by decreasing the rate of enzyme action. (Competitive and Non-competitive)
How do competitive inhibitors function?
Bind to the active site preventing the substrate from binding but can be overcome by increasing substrate concentration
How do non-competitive inhibitors function?
Attach to a non-active site causing a change in the shape of active site and cannot be reversed by increasing substrate concentration
How does feedback inhibition function?
It happens as the concentration of end product builds up and reaches critical concentration inhibiting an earlier enzyme, blocking the pathway = prevents further synthesis of end product
