8.1 Flashcards
What is a metabolic pathway
any chain or cycle of linked reactions catalyses by enzymes
What is an example of a metabolic pathway
glycolysis
What is a link reaction
when metabolic pathways are linked to other pathways such as how glycolysis is linked to the Krebs cycle
What is the link reaction
When pyruvate forms acetyl CoA
3 carbon atoms to 2 carbon atoms
What happens to pyruvate if oxygen is present
it is transported into the mitochondrial matrix for the next stages of respiration
What takes place in the link reaction
conversion of pyruvate of a two carbon acetyl and takes place in the mitochondrial matrix
3 carbon forms two carbon
what is removed in the link reaction
a carboxyl group and hydrogen atom is removed from the pyruvate
What is decarboxylation
when a carboxyl group si s removed from the process
What is dehydrogenation when hydrogen atoms are removed
when hydrogen atoms are removed
what enzyme catalyses decarboxylation and dehydrogenation
pyruvate dehydrogenase
What happens when the carboxyl groups is removed from the pyruvate
Two carbons are produced in the acetyl final product
carbon dioxide as a product
What happens when the hydrogen atoms are removed from the pyruvate
they are accepted by NAD
NAD is reduced into NADH +H
What does the decarboxylation and dehydrogenation of pyruvate result in
the result of an acetyl group
What does an acetyl group
two carbons
What happens at the end of the link reaction
the two carbon acrylic combines with Coenzyme A (CoA) forming Acetyl - CoA
What is the activation energy
the minimum energy that reacting particles need to possess in order for a reaction to take place
A metabolic pathway
begins with a particular substrate, terminates with an end product and has many steps in between
What are two types of enzyme inhibitors
competitive and non-competitive
What does a competitive inhibitor do
competes with the substrate for the same active site
What does the non-competitive inhibitor do
buns at a site away from the active site - allosteric site - altering the shape of the enzyme
How is the maximum rate of reaction different with each inhibitor
with competitive inhibition, the rates eventually the same, as the substrate concentration increases, the rate will increase because there is more available substrate than the inhibitor
in non competitive inhibition, the rate levels off and never reaches the same level because all the enzyme molecules are effectively blocked from reaction with the substrate due to modification of their active site.
compare competitive and non-competitive inhibitors
chemically similar to the substrate - it has no similarity to the substrate
it binds to the active site of the enzyme - it binds to the enzyme at a site other than the active site
binding of the inhibitor does not modify the active site - binding of the inhibitor modifies the active site `
as the concentration of the substrate is increased, the effect of the inhibitor on the reaction is reduced - increasing the concentration of the substrate does not decrease the impact of the inhibitor, therefore the rate of reaction is lower than normal at all substrate concentrations
What can reduce the effect of competitive inhibition of an enzyme?
increasing the substrate concentration
What usually happens in end product inhibition
the enzyme that catalyses the first reaction o the pathway are allosterically inhibited by the end product of the pathway
