Metabolic Pathways Flashcards
What are metabolic pathways?
Metabolic pathways and integrated and controlled pathways of enzyme catalysed reactions within a cell.
What pathways can metabolic pathways undergo?
Reversible, irreversible and alternative routes.
What are anabolic reactions?
Anabolic reactions build up large molecules from smaller molecules and require energy to do so.
What are catabolic reactions?
Catabolic reactions break down large molecules into smaller molecules and release energy.
What controls metabolic pathways?
Metabolic pathways are controlled by the presence or absence of particular enzymes.
What is induced fit?
Induced fit is a process by which the active site of an enzyme changes to better fit the substrate it is acting on.
When does induced fit occur?
Induced fit occurs when the active site changes shape to better fit the substrate * after the substrate binds * this lowers activation energy and the energy required to reach transition state whilst weakening chemical bonds
What is meant by affinity?
Affinity is a word used to describe chemical attraction
What is the affinity between substrate molecules and the active site of an enzyme?
The affinity is high, allowing the substrate molecules to bind to the active site.
What is the affinity like between products and the active site?
The affinity is low, allowing products to leave the active site.
What are the effects of substrate and product concentration on the direction and rate of enzyme reactions?
Some metabolic reactions are reversible and the presence of a substrate or removal of a product will drive a sequence of reactions in a particular direction
EG. Critically high product concentration results in slower rate of reaction
High substrate concentration results in a faster rate of reaction
How are metabolic pathways controlled? ( 3 ways )
Competitive inhibition
Non-Competitive inhibition
Feedback inhibition
What is the role of competitive inhibitiors
Competitive inhibitors bind at the active site preventing the substrate from binding.
Competitive inhibition can be reversed by increasing the substrate concentration.
What is the role of non-competitive inhibitors?
Non-competitive inhibitors bind away from the active site to the allosteric site, changing the shape of the active site and preventing the substrate from binding. This process is irreversible.
What is feedback inhibition?
Feedback inhibition occurs when the end-product in a metabolic pathway reaches a critical concentration. This end-product then inhibits an earlier enzyme, blocking the pathway and preventing further synthesis of that end product.
