1.6 Metabolic Pathways Flashcards
What are metabolic pathways?
Metabolic pathways are integrated and controlled pathways of enzyme-catalysed reactions within a cell
What steps can metabolic pathways have?
Reversible and irreversible
What do alternative metabolic pathways do?
The bypass steps in a pathway
What is an anabolic reaction?
A build up of large molecules from small molecules and require energy
What is a catabolic reaction?
A break down of large molecules into smaller molecules and release energy
What are metabolic pathways controlled by?
The absence or presence of particular enzymes. They are also controlled through the regulation of the rate of the reaction of key enzymes within the pathway
What is the active site?
The active site is where the substrate will bind to on the enzyme
What do substrates show a high affinity for?
The enzymes active site
What happens to the shape of the active site when a substrate molecule enters?
The shape of the active site changes slightly to better fit the substrate. This is called induced fit
What happens to the affinity for the active site one a reaction has occurred?
The affinity becomes low
What direction does a metabolic pathway go in?
Reversible
What will drive a metabolic reaction forward?
The presence of substrate and removal of product
What will drive a metabolic pathway backwards?
Absence of substrate and build up of product
What is the job of a competitive inhibitor?
They bind to the active site and prevent the substrate from binding
How do you reverse a competitive inhibitor?
By increasing the substrate concentration making it more likely that the substrate will enter the active site before the inhibitor
What do non-competitive inhibitor do?
They bind away from the active site to another part of the enzymes
What happens to the active site when a non-competitive inhibitor is in place?
Changes the shape of the active site and prevents the substrate from binding
When does feedback inhibition occur?
When the end-product in the pathway reaches a critical condition
What happens when the end-product inhibits an earlier enzyme?
It blocks the pathway and prevents further end-product from being made
