1.6 Flashcards
what are metabolic pathways
metabolic pathways are integrated and controlled pathways of enzyme catalyzed reaction within a cell
what ways do anabolic and catabolic pathways run down
these pathways can have reversible , irreversible steps and alternative routes
anabolic pathway
Requires energy and builds up (synthesises) small molecules into larger molecules.
catabolic pathway
Releases energy and breaks down large molecules into smaller molecules (degradation).
how are metabolic pathways controlled
metabolic pathways can be controlled through the presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes within a pathway .
what is Activation energy
activation energy is needed to break chemical bonds in the reactant chemicals .
induced fit lowers the activation energy needed by reactants and increases reaction rate.
induced fit
induced fit is the change when a molecule of substrate enters the active site. The enzyme is specific to its substrate. It will bind to one particular substrate because the shape of the active site has to match the shape of the substrate. The substrate has a high affinity for the active site . the resulting products have a low affinity for the active site and so leave the active site.
what are the three types of enzyme inhibitation
competitive
non competitive
feedback inhibitation
competitive inhibitation
Competitive Inhibitors bind at the active site preventing the substrate from binding.
Competitive inhibition can be reversed by increasing the substrate concentration.
non competitive inhibitation
Non-competitive inhibitors bind away from the active site but change the shape of the active site which prevents the substrate from binding.
This cannot be reversed by increasing substrate concentration.
feedback inhibition - end product
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 so prevents further synthesis of an end product..
how does the substrate concentration affect the rate of reaction
increasing substrate concentration will increase the enzyme reaction until all of the actives sites are occupied by the substrate.
how can the rate of enzyme reaction be affected
temperature, pH and substrate concentration.
