U1KA6 Flashcards
What are metabolic pathways?
They are integrated and controlled pathways of enzyme-catalysed reaction within a cell.
Do metabolic pathways have reversible steps?
They can have reversible steps, irreversible steps and alternative routes.
How are metabolic pathways helpful by having reversible/irreversible steps and alternative routes?
They help make sure a steady supply of products or make sure that too many products are not produced.
What is an anabolic reaction?
Build up large molecules from small molecules, require energy.
What is a catabolic reaction?
Break down large molecules into smaller molecules, release energy.
What is needed to carry out any enzyme reaction?
energy input.
What is the energy required for a reaction to occur known as?
activation energy.
What happens when enzymes lower activation energy?
making it more likely a reaction will occur, increasing reaction rate.
What is an induced fit?
when a complementary substrate enters the active site of an enzyme, the active site changes shape to better fit the substrate.
What does an induced fit do to the reaction?
Lowers the activation energy for the reaction to occur.
Substrates have ______ for the active site of an enzyme, meaning ______
high affinity, meaning that they move easily into the active site.
Products have _____ for the active site, meaning _______
low affinity, meaning that they move out of the active site, freeing it up for more reaction to occur.
What is enzyme activity affected by?
temperature, pH, substrate concentration and product concentration.
What happens when low concentration of substrate is present?
Enzyme activity is low due to the low number of interactions betweens substrates and enzymes. Both substrate concentration and enzyme activity increase due to increasing interaction between enzymes and substrates. Enzyme activity stops increasing due to enzyme active sites being occupied, no longer being able to carry out a faster reaction.
How do enzymes [prevent over-production of a product?
some enzymes work in reverse direction if product concentration is far too high.
Are enzymes affected by product concentration?
Yes, as product concentration increases, enzymes activity decreases.
What are enzyme inhibitors?
They are inhibitors that block or reduce the action go enzymes.
What are the three types of enzyme inhibitors?
competitive inhibitors, non-competitive inhibitors and feedback inhibitors.
How do competitive inhibitors block or reduce the action of enzymes?
by binding at the active site preventing the substrated from binding.
Can competitive inhibitors be reversed?
yes, by increasing substrate concentration.
How do non-competitive inhibitors block or reduce the action fo enzymes?
by binding away from the active site but change the shape of the active site preventing substrate from binding.
Is non-competitive inhibition reversable?
no, cannot be reversed by increasing substrate concentration.
