1. Enzymes

2. Chemical Reactions
In order for chemical reactions to take place, enzymes must be present to help speed up the reaction.
Chemical bonds connect atoms
to make molecules.
Chemical reactions can do two things:
They can join atoms to make molecules.
They can break bonds in molecules.
The sum of all the chemical reactions that take place within a cell is referred to as the cell’s metabolism.

3. Chemical Reactions
The molecules or atoms at the beginning of a chemical reaction are called the reactants.
The materials produced by the chemical reaction are called products.
2H O  H2O
Reactants Product

4. Law of Conservation of Matter/Energy
Matter and Energy cannot be created or destroyed in chemical reactions

5. Energy-Absorbing vs. Energy-Releasing Reactions
Endothermic Reaction
Energy-Absorbing Reaction
Energy-Releasing Reaction

6. Enzymes Reactants Products Active sites
The molecules or atoms at the beginning of a chemical reactions are called ______.
Enzymes
Reactants
Products
Active sites

7. Energy-Releasing Energy-Absorbing
Chemical reactions in which the products have more energy than the reactants are called _________ reactions.
Energy-Releasing
Energy-Absorbing

8. Which graph illustrates an energy-releasing reaction?
Graph A
Graph B

9. Introduction to Enzymes
Enzymes are proteins that act as biological catalysts.
Catalysts - speed up chemical reactions.
Enzymes- speed up chemical reactions in living things.

10. Structure and Function of Enzymes
A substrate is the molecule that the enzyme changes.
It is the reactant a chemical reaction controlled by an enzyme!
Each enzyme has an active site which is the place where the enzyme and substrate attach.

11. Structure and Function of Enzymes
During a chemical reaction, the enzyme helps the reactant turn into product, however, the enzyme is not changed.
Enzymes can be used over and over again.
Product
Reactant/Substrate
Enzyme
No change in the shape of enzyme/ready to catalyze next reaction.

12. Enzymes are specific types of which biological macromolecule?
Carbohydrates
Proteins
Lipids
Nucleic acids

13. The molecule on which an enzyme acts:
Catalyst
Substrate
Metabolism
Homeostasis

14. Which shape is the enzyme?B C D D D B C A A A

15. Which shape is the product of the chemical reaction shown below?

16. Enzyme Specificity
Enzymes are very specific. This means that each enzyme can only work on one substrate.
For example:
1. Maltase only breaks down maltose (a carbohydrate).
2. Lipase only works on certain lipids.
3. Protease only works on certain proteins.
Does a specific enzyme work on more than one substrate?
NO!!!

17. Enzyme Specificity
Therefore you need thousands of different enzymes for the thousands of different chemical reactions in your body.
The names of many enzymes (Amylase, Lipase, Pepsin, Trypsin) usually end in ase or in.

18. Enzyme Specificity
The diagram below shows the lock and key model of how enzymes work on a specific substrate.
Just like every lock has one type of key that opens it, every substrate has one type of enzyme that works on it.

19. How Enzymes Work Lower activation energy
Energy that is needed to start a chemical reaction
Puts substrates in a good position to make/break bonds with each other

20. Reaction with enzyme vs. Reaction without enzyme

21. The energy that is required to start a chemical reaction is called
Endothermic energy
Exothermic energy
Enzyme energy
Activation energy

22. How do catalysts speed up or facilitate chemical reactions?
Lower the activation energy
Add energy to the reaction
Break hydrogen bonds in the chemicals
Decrease the number of reactants

23. Enzymes lower activation energy

24. Enzymes and Their Environment
Most cells function best within a narrow range of temperature and pH.
At very low temperatures, enzymes work too slow.

25. Enzymes and Their Environment
At high temperatures or extremes of pH the enzymes lose their shape.
What would happen if a key lost its shape?
It wouldn’t turn or fit in the hole.
What will happen if an enzyme lost its shape?
It wouldn’t recognize or bind with it’s substrate.

26. Enzymes and Their Environment
When an enzyme loses its shape and can no longer work correctly, it has been denatured.

27. Enzymes stop functioning if:
They act on a substrate
They become denatured due to improper pH or temperature
They catalyze too many reactions
They bind with the wrong substrate

28. Passive Endothermic Exothermic Denatured
When proteins, such as enzymes, lose their specific shape they have become __________.
Passive
Endothermic
Exothermic
Denatured

29. What is the optimum pH for the enzyme pepsin?1
2.5 5
6.5
trypsin
pepsin

30. Introduction to Macromolecules

31. Building Macromolecules
Polymer – large biomolecules made by linking together a large number of the same type of subunit
Monomer- small molecule that is a subunit of a polymer (building blocks)
Chemical reactions link monomers together to build polymers or break down polymers into monomers
Enzymes help speed up these reactions!!

32. Organic Macromolecules (Polymers)
MONOMER
POLYMER
Amino Acid
Protein
Sugar
(monosaccharide)
Carbohydrate
(polysaccharide)
Nucleotide
Nucleic Acid

33. Polymers are large biomolecules made of repeated subunits called
Enzymes
Sugars
Monomers
Proteins

34. Proteins are polymers made of monomers called
Monosaccharides
Fatty acids
Amino acids
nucleotides