2.4 – chemical reactions and enzymes - quia · 2.4 – chemical reactions and enzymes . regents...

19
Regents Biology 2.4 – Chemical Reactions and Enzymes

Upload: vanque

Post on 27-Aug-2018

228 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

2.4 – Chemical Reactions and Enzymes

Page 2: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Chemical reactions of life §  Processes of life involve

-  building molecules (forming bonds)

-  breaking down molecules (breaking bonds)

+

+

Page 3: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Dehydration vs. Hydrolysis § dehydration synthesis (synthesis)

§ hydrolysis (digestion)

Page 4: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Chemical Reactions and Energy §  Chemical reactions that release energy often occur

spontaneously.

Page 5: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Chemical Reactions and Energy §  Chemical reactions that absorb energy will NOT occur

without a source of energy.

§  Activation energy – energy needed to get reactants to become unstable enough to react with each other (for both types of reactions)

Page 6: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Activation energy §  is energy that moves the reaction over an “energy

hill” §  How is this energy supplied? §  Heat

glucose

Not a match! That’s too much energy to expose living cells to!

Page 7: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Reducing Activation energy §  But applying heat to the whole system might be bad. §  How else to supply this energy? §  Catalysts (enzymes) reduce the amount of energy to

start a reaction.

reactant

product

uncatalyzed reaction

catalyzed reaction

NEW activation energy

Pheeew… that takes a lot

less energy!

Page 8: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

What’s going here?

Page 9: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

How important are enzymes? §  ALL chemical reactions in living organisms require

energy to work.

§  Enzymes reduce activation

energy, thus speed up reactions Ex: catalase helps break down hydrogen peroxide fast

Page 10: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Enzymes in detergents

Page 11: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

What else about enzymes? §  Enzymes are mostly proteins. §  Each enzyme helps a specific reaction. §  Each enzyme needs to be the right

SHAPE for the job. §  Enzymes are named for the reaction

they help. Ex:

§  sucrase breaks down sucrose § proteases breakdown proteins §  lipases breakdown lipids § DNA polymerase builds DNA

Oh, I get it! They end in -ase

Page 12: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Sucrase

§  Enzymes are NOT changed or used up by the reaction.

Page 13: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

It’s SHAPE again! §  Lock and Key Model - shape of protein allows the

substrate to fit into the enzyme so that a chemical reaction can occur.

Page 14: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Wrong shape? §  insecticide Malathion §  Penicillin

Page 15: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

What affects enzyme action §  Correct order of amino acids - why? - enzyme has to be right

shape §  Temperature - why? - enzyme has to be right

shape §  pH - why? - enzyme has to be right

shape

Page 16: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Order of amino acids §  Wrong order = wrong shape = can’t do its job!

chain of amino acids

chain of amino acids

folded protein

folded protein

right shape!

wrong shape!

Page 17: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Effect of Temperature on Enzyme Activity -  ideal (optimum) temperatures allow for greatest number

of collisions between enzyme and substrate -  too high or too low temperatures cause proteins to lose

their shape (denaturation)

37° temperature

reac

tion

rate

Page 18: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology 7

Effect of pH on Enzyme Activity

pH

reac

tion

rate

2 0 1 3 4 5 6 8 9 10

stomach pepsin

intestines trypsin

11 12 13 14

-  optimum pH for most human enzymes is around 6-8 -  too high or too low pHs cause proteins to lose their

shape (denaturation) although…

Page 19: 2.4 – Chemical Reactions and Enzymes - Quia · 2.4 – Chemical Reactions and Enzymes . Regents Biology! Chemical reactions of life ! Processes of life involve - building molecules

Regents Biology

Enzymes