enzymes

Question 1

cofactor definition

Answer 1

a non-protein substance that has to be present to ensure the enzyme- catalysed reaction takes place at an appropriate rate.

Question 2

cofactors- prosthetic group

Answer 2

a co-factor that is permanently bound to the enzymes active site by covalent bonds.
Zinc ions (Zn2+) are prosthetic groups for the enzyme- carbonic anhydrase
catalyses the formation of carbonic acid H2CO3 from CO2 and water so that it can from hydrogen carbonate ions HCO3- which can be transported in the blood

Question 3

Cofactors

Answer 3

presence of an ion that is not permanently bound
Binds temporarily to the enzyme or the substrate to ease the formation of enzyme-substrate complexes.
Amylase- catalyses hydrolysis of starch to maltose only works in presence of Cl- ions

Question 4

Co-enzymes

Answer 4

Organic molecules
Temporarily bind the enzymes active site
The co-enzymes are chemically changed during reaction, so need to be recycled.
Many co-enzymes are derived from water-soluble enzymes.

Question 5

How can activation energy be reduced? Anabolic

Answer 5

Substrate molecules attaching to an enzyme brings them closer together, reducing any repulsion. so they can bind together more easy

Question 6

How can activation energy be reduced? Catabolic

Answer 6

A substrate molecule fitting into an active site puts strain on the bonds in the substrate molecule meaning they break up more easily

Question 7

Inhibitors

Answer 7

Substances that reduce activity of an enzyme or stops the reaction

Question 8

Competitive inhibition

Answer 8

Similar shape to substrate
Compete with substrate for space in active site
Block AS so no substrate molecules can fit
The amount of inhibition depends on relative concentration of inhibitor and substrate
More inhibitor molecules means more collisions with active site and greater effect of inhibition
They form an enzyme-inhibitor complex that makes them catalytically inactive
Prevent substrate molecules from joined- no e-s can form.
But it is reversible, increasing conc of substrate reduces the effect of competitive inhibition
CAN STILL REACH MAX BUT JUST TAKES LONGER AND RATE OF REACTION INCREASES AS SUBSTRATE CONC DOES.

Question 9

NON COMPETITIVE INHIBITION

Answer 9

Non-competitive inhibitors do not compete with the substrate molecules for a place in the enzymes active site.
They attach to the enzyme’s allosteric site.
This disrupts the enzyme’s tertiary structure and hence, its shape.
This distorts the enzyme’s active site so it is no longer complementary to the substrate molecule
So no E-S can form
It is an irreversible change
The maximum rate is reduced- adding more substrate molecules makes no difference. ror reduced