enzymes 1

Question 1

enzymes

Answer 1

protein catalysts: increase the rate of chemical reactions
bind substrates
release products
act as a point of regulation

Question 2

enzymes reactions

Answer 2

modified but always return to their original from they are not used up

Question 3

enzymes and metabolic pathways

Answer 3

combined catalytic activities offer control

short and long term control

Question 4

enzymes and cell dysfunction

Answer 4

over and under expression= cell dysfunction

• target for therapeutics
• monitor to asses disease states

Question 5

ending in -ase

Answer 5

commission rules permit 6 groups

based on the chemical reaction bin catalysed

Question 6

substrate-binding sites

Answer 6

substrates bind to specific sites via interactions with enzymes amino acids
spatial geometry dictates specificity

Question 7

active catalytic site

Answer 7

region where reaction occurs
functional groups present include co-enzymes, metal ions and amino acid residues
it is a crevice formed by polypeptide chains: 3d arrangements permits reacting substrates to approach each other

Question 8

activation energy

Answer 8

the substrate is activated by functional groups
is the difference between substrates and transition-state complex
enzyme decrease the activation energy

Question 9

pH and temperature profiles

Answer 9

functional pH and temperature range
increased temperature- increased reaction rate
— denaturation

Question 10

enzyme-catalysed 3 steps

Answer 10

enzyme - substrate enter - enzyme+substarte - enzyme+product - product leaves - enzyme

Question 11

substrate binding lock-key model

Answer 11

complementary 3d surface that recognises the substrate: it binds through hydrophobic, electrostatic interactions and hydrogen bonds
charge
can be prevented by steric hindrance and charge repulsion

Question 12

induced fit model

Answer 12

as substrates bind enzymes undergo conformational change :
side chains of amino acids(active site) reposition
binding interactions increase
not rigid lock but a dynamic surface

Question 13

transition state complex

Answer 13

unstable high-energy complex with strained electronic configuration

by binding substrates to active sites= lowers transition state(high energy state) so less energy needed to attain it

Question 14

transition state

Answer 14

bonds become maximally strained

Question 15

reaction rate

Answer 15

determined by no of molecules acquiring activation energy
enzymes decrease the activation energy
faster reactions with enzymes

Question 16

prothetic groups

Answer 16

tightly bound cofactors

Question 17

catalytic properties

Answer 17

dependent on non-peptide molecules called cofactors or coenzymes

Question 18

cofactors or coenzymes

Answer 18

are what give catalytic properties to enzymes
non-peptide molecules
synthesised from vitamins– importance of diet

Question 19

lactas dehydrogenase

Answer 19

turns sugar into energy

catalyses the transfer of electrons from lactate to NAD+
uses coenzyme NAD+ synthesised from vitamin niacin and ATP
substrate binds to enzyme and changes conformation