Enzymes

Question 1

structure of enzymes

Answer 1

attach to substrates by the active site, active sites are specific, the 3D shape of enzymes allows them to also be specific

Question 2

are enzymes reactants

Answer 2

no as they are not destroyed or used up during a chemical reaction

Question 3

function of enzymes

Answer 3

catalysts in chemical reactions, the work by lowering the activation energy required by a cell therefore increasing reaction rate

Question 4

two ways enzymes can attach to substrates

Answer 4

induced fit model theory, lock and key model theory

Question 5

induced fit model theory

Answer 5

enzymes alter their shape to fit the substrate, the active site continues to change until the substrate is completeley bound to it, only then will the final shaoe and charge be determined

Question 6

lock and key model theory

Answer 6

the shape of the substrate exactly matches/is complementary to the active site of the enzymes, no change is necessary from the active site or substrate in order to bind together

Question 7

when is an enzyme considered denatured

Answer 7

when the active site is altered to the point it can no longer attach to the substrate, therefore a denatured enzyme cannot catalyse a reaction, it cannot be restored to its original shape, denaturation is permanenet

Question 8

what causes an enzyme to denature

Answer 8

changes in temps and pH’s of the enzymes environment

Question 9

for enzymes, what affects rate of reaction

Answer 9

temp, pH, concentration of enzymes, concentration of substrates, inhibitors, cofactors and coenzymes

Question 10

how does concentration of enzymes and substrates affect rate of reaction

Answer 10

more enzymes and more substrates= more collisions so moree reactions, the increase will only continue if there is an enzyme/substrate supply that is endless, if not point of saturation is reached

Question 11

types of inhibitors

Answer 11

competitive, non-competitive, irreversable, reversible

Question 12

irreversible inhibitors

Answer 12

bind to enzyme with strong covalent bonds that chhange the protein chemically which cant be reversed

Question 13

inhibitors

Answer 13

substances that bind to the enzyme and stop it from working to its full capacity

Question 14

reversible inhibitors

Answer 14

bind non-covalently to enzymes, non covalent bonds are easily broken therefore seperating the inhibitor and enzyme which can then continue catalysing as normal

Question 15

competitive inhibitors

Answer 15

have a similar shape yo tthe substrate so bind to the active site, making it difficult for the substrate to bind to the active site, they don’t change the active site and can be removed by increasing substrate concentration

Question 16

non-competitive inhibitors

Answer 16

bind to part of the 3D shape which is not the active site, instead it is the allosteric site, this changes the 3D shape of the protein including the active site, decreasint the enzymes catalysing ability, increase substrate concentration has no affect

Question 17

why does end product inhibition occur

Answer 17

in many biochemical pathways, the end product becomes the substrate of the next reaction, when enough of the substrate is produced, the cell no longer needs to produce that substrate

Question 18

what is end product inhibition

Answer 18

when a biochemical pathway is shut down, this occurs when the substrate attaches to the first enzyme of the pathway ar is allosteric site, causing it to be ineffective, shutting down the pathway

Question 19

how does atp act as a coenzyme

Answer 19

atp attaches to the active site of the enzyme, giving energy required for the reaction to take place, it loses one phosphate atom in tthe process, then leaaves the enzyme where the enzyme can be replaced with another atp

Question 20

how does NADH and NADPH act as a cofactor

Answer 20

attaches to the active site, provides energy for reaction, loses hydrogen atom in the process which changes it shape, leaves the enzyme to become loaded again