1. Section 2.5 Enzymes

2. Word Splash Enzyme Active Site Biological Catalyst Activation Energy
Substrate Denatured
Lock and Key Reusable

3. Key Concept
Enzymes are proteins that speed up chemical rxns in living cells by lowering the amount of activation energy (EA) needed to get them started
proteins
catalyst

4. Chemical Reactions require E
Energy is needed to start a chemical reaction.
This energy is used to break the bonds between
atoms in the reactant molecules so they are free
to recombine in new ways
The amount of energy needed is called activation energy (Ea).
Weakening bonds
Lowering

5. Function of Enzymes Enzymes make rxns go faster by
reducing the amount of activation energy
needed for the reaction to start

6. Activation Energy
What’s needed to get the rock rolling down the hill on its own?
ENERGY INPUT

7. Enzymes are Biological Catalysts
A catalyst speeds up the rate of the reaction by reducing the amount of activation energy needed to start the reaction.
Because enzymes have the job of catalysts in living things they’re called biological catalysts.

8. How Enzymes Work
Enzymes are protein molecules.

9. Enzyme Shape determines Function
Each enzyme has a unique shape with a special area called an active site

10. Enzyme – Substrate Complex
One or more molecules called substrates bond to the enzyme’s active site.
Together they form an enzyme –substrate complex.

11. Lock and Key Theory
An enzyme’s specific shape allows it to fit with only one substrate like a
lock and key.

12. Enzyme – Substrate Complex
Once the enzyme and substrate combine a shape change occurs.

13. Enzymes help reactions go faster
The shape change provides the energy needed to break or form bonds in the substrate so that new molecules , called products, can be formed .
They are then released from the active site.

14. An enzyme flick
Let the show begin....

15. Enzymes
Enzymes are reusable – they can be used over and over again to catalyze / speed up a specific reaction.

16. Enzymes are Unique
Each enzyme is unique in its shape and catalytic activity.
Different environmental factors affect how well an enzyme works.
Environmental conditions that cause each type of enzyme to work its best – Optimal condition

17. Factors that Affect Enzyme ActivitypH
Temperature
Substrate Concentration-amount of substrate molecules
Enzyme Concentration- amount of available enzyme

18. Optimal Conditions
The environmental conditions that cause each type of enzyme to work its best are called – optimal level.
For example, ° is the optimal temperature for enzymes to work in the human body.

19. Enzyme Activity Graphs

20. Affect of Substrate Concentration

21. Enzymes can be Denatured
Certain conditions can cause an enzyme’s shape to change. If an enzyme’s shape changes it cannot do its job. This is called denatured

22. Many diseases are caused by a missing or defective enzyme
Many diseases are caused by a missing or defective enzyme. Lactose intolerance – missing lactase______________ __________________________________________ Phenylketonuria (PKU) – missing phenylketonurase.

23. Enzyme Activity Graph with zones of activity/inactivity

24. Quick Facts about Enzymes
Enzymes are protein molecules
Enzymes function to make reactions
go faster
Are reusable
There are about 2000 different enzymes in each one of your cells
Each enzyme fits with only
________ substrate molecule
Names usually end in -ase
specific
reusable
ase

25. General Types of Enzymes
Amylases –
break starch to glucose
Lipases –
break lipids to fatty acids
Proteases –
break proteins to
amino acids
Nucleases – break nucleic acids DNA and RNA to nucleotides

26. Factors that affect Enzyme Action

27. How do enzymes work?
Each enzyme has a unique 3-D shape, including a surface groove called an ACTIVE SITE.
One or more molecules called SUBSTRATES chemically bond to the enzyme’s active site.
When joined they are called an ENZYME-SUBSTRATE COMPLEX
Changes in how the atoms are bonded occur resulting in new molecules being made called PRODUCTS .
Products are then released from the active site.
Active site
Substrate
Product