Metabolic Pathways Flashcards
(14 cards)
What are metabolic pathways?
They’re integrated and controlled pathways of enzyme-catalysed reactions within a cell
What are the three types of metabolic pathways?
Reversible steps(stages can be altered)
Irreversible steps(some reactions are permanent)
Alternative routes(more than one route to the end product make more simple, may exist if enzyme isn’t produced and can bypass pathway steps)
What are the two reactions within metabolic pathways?
Anabolic
Catabolic
What are anabolic reactions?
Do they require energy?
The build up of smaller subtrates/molecules to create a larger product/molecules, input of energy required
What are catabolic reactions?
Do they require energy?
The breakdown of one larger substrate/molecules to create smaller products/molecules, releases energy
What are metabolic pathways controlled by?
The presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes
When does induced fit occur?
What does this do to the activation energy?
When the active site changes shape to better fit the substrate after the substrate binds
This lowers the activation energy needed for the reaction
What is the affinity for the active site like for substrates and products?
Substrates have a high affinity for the active site
Products have a low affinity for the active site(allowing them to leave more easily)
What can happen to reversible metabolic reactions with the presence of a substrate or the removal of a product?
It will drive a sequence of reactions in a particular direction
What happens when you increase the substrate concentration?
More enzyme reacts with the substrate and increase the rate of reaction until all active sites are occupied
Once occupied the reaction levels off and remain constant no matter how much substrate is added
What are inhibitors?
Chemicals that slow down/stop a chemical reaction
What are competitive inhibitors?
They bind at the active site preventing the substrate from binding
Its reversed by increasing substrate concentration(reduces their effect)
What are non competitive inhibitors?
Can it be reversed?
They bind away from the active site but change the shape of the active site preventing the substrate from binding
It cannot be reversed by increasing substrate concentration(don’t bind at active site)
What is feedback inhibition?
Occurs when the end product in the metabolic pathways reaches a critical concentration
The end product then inhibits an earlier enzyme blocking the pathway and so preventing further synthesis of the end product
