Metabolic Pathway 2.1 Flashcards
What are metabolic pathways?
Metabolic pathways are integrated and controlled pathways of enzyme-catalysed
reactions within a cell.
What kind of steps can metabolic pathways have?
reversible steps, irreversible steps and alternative
routes.
What is an anabolic reaction?
Anabolic reactions build up large molecules from small molecules and require energy.
What is a catabolic reaction?
Catabolic reactions break down large molecules into smaller molecules and release
energy.
What is embedded in the membrane?
Protein pores, pumps and enzymes are embedded in membranes.
What are metabolic pathways controlled by?
Metabolic pathways are controlled by the presence or absence of particular
enzymes and the regulation of the rate of reaction of key enzymes.
What is induced fit?
Induced fit occurs when the active site changes shape to
better fit the substrate after the substrate binds.
How does induced fit affect the activation energy and affinity of the substrate and products for the active site ?
The substrate molecule(s) have a high affinity for the
active site and the subsequent products have a low
affinity, allowing them to leave the active site.
How does substrate and product concentration affect the direction and rate of enzyme reactions?
Some metabolic reactions are reversible and the
presence of a substrate or the removal of a product will drive a sequence of reactions in a particular direction.
What are competitive inhibitors? Can they be reversed or not?
Competitive Inhibitors bind at the active site preventing the substrate from binding.
Competitive inhibition can be reversed by increasing substrate concentration.
What are non-competitive inhibitors? Can they be reversed or not?
Non-competitive inhibitors bind away from the active site but change the shape of the active site preventing the substrate from binding. Non-competitive inhibition cannot be reversed by
increasing substrate conc.
What is Feedback Inhibition? What does it involve?
Feedback Inhibition occurs when the end product in the metabolic pathway reaches a critical concentration. The end-product then inhibits an earlier enzyme, blocking the pathway, and so prevents further synthesis of the end-product.
