1. Enzymes
Honors Biology

2. Chemical Reactions and Enzymes

3. Chemical Reactions and Enzymes
chemical reaction: process that changes one set of compounds (reactants) into another set of compounds (products)

4. Chemical Reactions and Enzymes
chemical reaction: process that changes one set of compounds (reactants) into another set of compounds (products)
A. example:
wood + oxygen  carbon dioxide + water + energy

5. Chemical Reactions and Enzymes
chemical reaction: process that changes one set of compounds (reactants) into another set of compounds (products)
A. example:
wood + oxygen  carbon dioxide + water + energy
Reactants

6. Chemical Reactions and Enzymes
chemical reaction: process that changes one set of compounds (reactants) into another set of compounds (products)
A. example:
wood + oxygen  carbon dioxide + water + energy
Reactants Products

7. Chemical Reactions and Enzymes
B. example:
carbon dioxide + water  glucose + oxygen

8. Chemical Reactions and Enzymes
B. example:
carbon dioxide + water  glucose + oxygen
Reactants

9. Chemical Reactions and Enzymes
B. example:
carbon dioxide + water  glucose + oxygen
Reactants Products

10. Chemical Reactions and Enzymes
B. example:
carbon dioxide + water  glucose + oxygen
Reactants Products
chemical equation:
CO H2O  C6H12O6 + O2

11. Chemical Reactions and Enzymes
B. example:
carbon dioxide + water  glucose + oxygen
Reactants Products
chemical equation:
CO H2O  C6H12O6 + O2
Reactants

12. Chemical Reactions and Enzymes
B. example:
carbon dioxide + water  glucose + oxygen
Reactants Products
chemical equation:
CO H2O  C6H12O O2
Reactants Products 6 6 6

13. Chemical Reactions and Enzymes
All reactions require some energy to start: activation energy.
Energy needed to break or make bonds

14. Chemical Reactions and Enzymes
All reactions require some energy to start: activation energy
+ energy
Cellulose (C, O, H) + O2
CO2 + H2O + heat

15. Chemical Reactions and Enzymes
All reactions require some energy to start: activation energy.
carbon dioxide + water  glucose + oxygen

16. Chemical Reactions and Enzymes
II. The speed of a reaction depends on whether it releases or absorbs energy.
Activation
energy
Products
Activation
energy
Reactants
Products
Reactants
Energy Absorbing
(Endothermic)
Energy Releasing
(Exothermic)

17. Chemical Reactions and Enzymes
B. catalyst: substance that speeds up a chemical reaction by lowering the activation energy

18. Chemical Reactions and Enzymes
Catalyst: substance that speeds up a chemical reaction by lowering the activation energy

19. Chemical Reactions and Enzymes
Catalysts found in living things are called enzymes
Enzymes are made of Proteins

20. Chemical Reactions and Enzymes
C. Enzymes
provide a site where the reactants of a chemical reaction can be brought together

21. Chemical Reactions and Enzymes
C. Enzymes
provide a site where the reactants of a chemical reaction can be brought together
are not used up or changed during the chemical reaction (Can be used again)

22. Chemical Reactions and Enzymes
active site: part of the enzyme where the reactants bind (stick)

23. Chemical Reactions and Enzymes
active site: part of enzyme where reactants bind
reactants: called substrate when they fit in enzyme
* (Reactants only fit into the active site of the correct enzyme like a lock and key)

28. IV. Enzymes only work in specific conditions
A. temperature: increases rate but then destroys the shape of the enzyme (protein) if too high
Why Fevers
can be deadly

29. Temperature or pH Change:
No Product Made

30. IV. Enzymes only work in specific conditions
B. pH: Enzymes have optimal pH but if pH changes, it changes the shape of the enzyme and its active site

31. IV. Enzymes only work in specific conditions
C. inhibitor molecules: block reactant from entering active site

33. Examples of Inhibitors
Ethanol (drinking alcohol) is metabolized by enzymes

34. A drug, disulfiram (Antabuse) blocks enzymes from breaking it down all the way, which causes the accumulation of acetaldehyde with subsequent unpleasant side-effects of nausea and vomiting
Used to help alcoholics stop drinking

35. Examples of Inhibitors
acetylcholine gives muscles the signal to contract, and then an enzyme acetycholinesterase breaks it down to stop contraction
Nerve Gas (chemical weapon) binds to acetycholinesterase and prevents it from working and letting muscles relax

37. IV. Enzymes only work in specific conditions
D. coenzymes: make enzymes work better

38. Factors affecting enzyme function
Substrate concentration
as  substrate =  reaction rate
more substrate = more frequently collide with enzyme
reaction rate levels off
all enzymes have active site engaged
enzyme is saturated
substrate concentration
reaction rate

39. Substrate Concentration
The reaction rate increases until the enzymes become saturated with substrate, and a maximum rate is reached

40. Peroxidase (Catalase) Enzyme

41. Warm-up #2
If a reaction involves the breaking of bonds, what type of reaction typically is it? (endothermic or exothermic)
How do enzymes speed up the rate of reaction?
What type of macromolecule are enzymes?
What is the lock-and-key model referring to concerning enzymes?
What enzyme breaks down amylose?
What are the reactants and products in the Liver Lab? And what enzyme will speed up the reaction?