4.1-4.4 enzymes Flashcards
(35 cards)
what is a non-competitive inhibitor and how does it work?
a non-competitive inhibitor binds to the allosteric site of an enzyme which changes the tertiary structure of the enzyme, disrupting the shape of the enzyme’s active site so the substrate can no longer fit in it.
what is a competitive inhibitor and how does it work?
a competitive inhibitor has a similar shape to the substrate so competes with the substrate for the active site and blocks it so that the substrate can no longer bind to the enzyme.
( however to counteract the effect of a competitive inhibitors you can increase the concentration of substrates)
what are reversible inhibitors?
the inhibitors are only temporarily binded to the active site as they have formed weak hydrogen and ionic bonds
what are irreversible inhibitors?
the inhibitors form covalent bonds with the enzyme which permanently inactive the enzyme.
how can you counteract the effect of irreversible inhibitors?
produce more enzymes
why do we need enzyme inhibitors?
-to prevent the build up of excess products
to regulate multi-step reactions
what is end-point inhibitions?
when the end product of a multi-step reaction is a non-competitive inhibitor for the enzyme needed in the first step of the reaction
is end-point inhibition reversible or irreversible
reversible
how is end-point inhibition reversible
the end product can detach so that th enzyme can be reactivated if it is needed
what is the purpose of an enzyme?
it is a biological catalyst that speeds up the rate of metabolic reactions in a living system without being used up
what makes up an enzyme?
it is a globular protein with a complex tertiary structure
what are intracellular enzymes?
enzymes that are produced and function within the cell
what is an example of an intracellular enzyme?
catalase
- converts hydrogen peroxide into water and oxygen to prevent cell damage
what is an extracellular enzyme?
an enzyme that is produced in the cell then secrets out of the cell to catalyse reactions outside of the cell
what is an example of an extracellular enzyme?
amylase
-breaks down starch molecules outside the cell as they are too big to enter the cell
how do enzymes help form biological molecules?
anabolic reaction where the hold substrates together and decrease minimise the repulsion so they bond
how do enzymes help break down biological molecules?
catabolic reaction where the active site puts strain on the substrate’s bonds to break them
explain the lock and key hypothesis
it states that the active site has a specific shape due to its complex tertiary shape and that the substrate has a complementary shape to precisely lock on to the enzyme.
however successful collisions are difficult because specific shape and angle needed for a substrate- enzyme complex
who founded the lock and key hypothesis and when?
Emil Fischer in the 1890’s
explain the induced-fit hypothesis
states that the enzyme undergoes a conformational change ( a subtle change to the R group ) to ensure it has an ideal binding arrangement for the substrate
who founded the induced-fit hypothesis and when?
Daniel koshland in 1959
what is a activator cofactor?
a non-protein inorganic ion (e.g Cl- ) or organic molecule known as a coenzyme
what does an activator cofactor do?
they temporarily bind to an enzyme and stabilises the structure of the enzyme so tat it can work.
they allow the enzyme to be activates in the area it is needed so that during transport from the site of production it doesn’t damage anything in the body
what is a coenzyme?
a complex organic molecule and type of cofactor made from vitamins (e.g vitamin B )
