Enzymes/proteins AS

Question 1

atoms in a protein

Answer 1

central carbon, amino group (NH3) carboxyl group (COOH) hydrogen atom (H) and variable R group

Question 2

reactions to make and break a poly and dipeptide

Answer 2

condensation makes peptide bonds and hydrolysis breaks them

Question 3

primary structure of a protein

Answer 3

sequence of amino acids in the polypeptide chain

Question 4

secondary structure of a protein

Answer 4

way the chain of amino acids of the polypeptide is folded. held by H bonds between NH group and C=O group

Question 5

tertiary structure of a protein

Answer 5

way the molecule is folded held by ionic/disulphide bonds

Question 6

name of place where substrate binds to

Answer 6

active site

Question 7

define enzymes

Answer 7

globular proteins. biological catalysts - speed up reactions but not used up. lower the activation energy needed to start reaction by weakening bonds when an enzyme substrate complex is formed

Question 8

points of lock and key model

Answer 8

active site does not change shape, complementary to substrate

Question 9

points of induced fit model

Answer 9

active site/enzyme not complimentary. active site changes shape when substrate binds. allows substrate to fit by distorting bonds

Question 10

effects of too high temperature on enzyme

Answer 10

hydrogen bonds break, denaturing enzymes, change in shape of active site fewer ES complexes formed. higher temp more enzymes denature

Question 11

effect of pH on enzymes

Answer 11

each enzyme has optimum pH. change in pH denatures enzymes. change in shape of active site. fewer ES complexes.

Question 12

effect of competitive inhibition

Answer 12

inhibitor complimentary to active site. binds with active site. prevent ES complexes being made

Question 13

effect of non-competitive inhibition

Answer 13

inhibitor attaches to enzymes (not active site) shape of active site altered substrate no longer fits. prevents ES complexes