Enzymes

Question 1

enzymes

Answer 1

boilogical catalysts
-enzymes lower AE so that reactions happen at lower temp, increased rate of reaction
-enzymes do this by putting strain on bonds in substrate so molecule breaks easier
FORM ENZYME SUBSTRATE COMPLEX

Question 2

coenzyme

Answer 2

inorganic cofactor, protein molecule that induces substrate fit

Question 3

cofactors

Answer 3

organic molecule fits into active site for an induced substrate fit
-some cofactors change the charge on surface of substrate/enzyme
-some cofactors temporarily bind with substrate

Question 4

2 models

Answer 4

Lock & key-substrate fits into enzyme active site and they have a complimentary shape
+shows how substrate fits into active site
Induced fit-substrate doesnt fit into enzyme so active site has to change slightly (may use cofactors)
-does not show how products are released

Question 5

Factors affecting enzyme activity

Answer 5

increased temp = increased kinetic energy & rate of reaction
PH-H bonds may break but if small change= H bonds can reform
enzyme conc
rate of reaction decreased if limited conc
-if substrate conc high - has no affect on rate as there are not enough enzymes

Question 6

Enzyme inhibitors

Answer 6

-a substrate that reduces or stops a reaction
competitive-substances that have similar shape to enzymes active site therefore fits in blocking substrate from entering and being catalysed
Non competitive- inhibitor binds to an allosteric site NOT the active site
-this distrupts the ezymes tertiary structure so that the enzyme is no longer complimentary

Question 7

End product inhibition

Answer 7

one way in which enzyme catalysed reactions may be regulated
-after catalysed reaction has reached completion, product molecules may stay tightly bound to the enzyme
-enzyme cannot form more of the product than the cell needs
negative feedback

Question 8

Medicinal drugs

Answer 8

-they inhibit/inactivate enzymes
aspirin-prevents formation of prostaglandins that are cell signalling molecules produced when cells are damaged
venom- contains chemical that inhibits enzyme acetylcholinesterase

Question 9

intracellular vs extracellular enzymes

Answer 9

intracellular-within a cell & its organelles
extracellular- act outside the cell (away from where it is produced)

Question 10

denaturing

Answer 10

if enzymes exceed optimum conditions then the tertiary structure of the enzyme will change meaning the active site is no longer complimentary
-it denatures as no longer works

Question 11

control of metabolic sequences

Answer 11

-product of one enzyme catalysed reaction becomes the substrate for the next enzyme catalysed reaction