1. ENZYMES http://www.kscience.co.uk/animations/model.swf

2. Figure 6.7 Enzymes Accelerate Chemical Reactions
How is lactose split into glucose and galactose? Without an enzyme, the amount of energy necessary to activate this reaction is high. In the presence of the enzyme lactase, however, a low activation energy is sufficient to get the process started. The energy released from the splitting of lactose is the same in both cases.

3. Figure 6.7 Enzymes Accelerate Chemical Reactions
How is lactose split into glucose and galactose? Without an enzyme, the amount of energy necessary to activate this reaction is high. In the presence of the enzyme lactase, however, a low activation energy is sufficient to get the process started. The energy released from the splitting of lactose is the same in both cases.

4. In all metabolic activities of our body and cells, lots of small molecules called ENZYMES work.
If we destroy enzymes in the body, all reactions will slow down and stop.
Because enzymes reduce activation energy of the reactions.
The minimum amount of energy that is needed to start the reaction is called ‘ ACTIVATION ENERGY ’

5. Substance which is used to decrease the activation energy of a reaction is called ‘ CATALYSTS ’ . Enzyme is a catalyst which is found in living organisms ; It REDUCES the activation energy and makes reaction FAST and EASY

6. Usually they are named as:
Heat can also decrease activation energy, but in cells heat can harm/denature molecules, so instead of heat enzymes speed up reactions.
Usually they are named as:
Enzyme that breaks down sucrose : SUCRASE
Enzyme that breaks down lipid : LIPASE
Sometimes they have special names .
For example : The enzyme that breaks down starch is called amylase.
-ase

7. STRUCTURE OF ENZYMES
Enzymes are PROTEINS. Enzyme synthesis is controlled by DNA (genes)
But in most enzymes protein part joins with other molecules. (SIMPLE AND COMPLEX ENZYMES)

8. COFACTOR( mineral )
Activated enzyme APOENZYME or
( HOLOENZYME ) COENZYME( vitamin )
1. Enzymes acts on their SUBSTRATES. A SUBSTRATE is the molecule that is affected by enzymes.
Enzyme+Substrate→ Enzyme-Substrate Complex → Enzyme + Products

9. c. b. a. d. f. e. substrate Active site Apoenzyme
Enzyme-subtrate complex d.
Products f.
Enzyme-subtrate complex e. 9

10. 1. Each enzyme has a specific substrate .
Properties of enzymes:
1. Each enzyme has a specific substrate .
2. The site that binds to substrate is called as ACTIVE SITE . The relation between an enzyme and its substrate is called LOCK AND KEY MODEL
3. The enzyme isn’t SPENT during reaction(only used), So it can be used MANY TIMES. (never changed)

11. 4. Reactions of Enzymes are Reversible.(not digestive ones)
Starch+ amylase enzyme glucose+ enzyme
5. Enzymes can’t work unless being water less than %15
6. Enzymes can work as a team. (ex.in digestion)
7. Enzymes are produced inside the cell but they can work inside OR outside of the cell.
8.Enzymes start their action from the outer surface of the substrate.

12. The factors that affect enzyme activity
1.TEMPERATURE :
At lower temperature ;the reactions slows down or stops but as the temperature increases the rate of the reaction increases until optimum. But denatures after 60 C.

13. 2.pH :
Each enzyme works best at a certain pH ,that is called optimum pH.
( Ex: Optimum pH=2 in the stomach for digestion )
Enzymes are (denatured) broken down above or below the optimal pH.

14. 3. WATER Enzymes can’t work unless being water less than %15.
Ex : Dry plant seeds can’t germinate

15. 4.CONCENTRATION OF ENZYME
Increasing the enzyme concentration increases the rate of reaction.
But after all substrate molecules are used and no change will be in the rate of reaction

16. 16

17. 5.CONCENTRATION OF SUBSTRATE
If we increase the concentration of substrate, the rate of the reaction increases. But after all enzyme molecules are full, they can not change the rate of reaction.

18. 6. SURFACE AREA OF THE SUBSTRATE
increasing the surface area of substrate,increases the activity of enzymes
Substrate surface

19. For example ; if we cut meat into pieces to make the surface bigger
For example ; if we cut meat into pieces to make the surface bigger. Minced meat is digested easier than a piece of meat.
Enzyme activity

20. 6.INHIBITORS
Some chemicals like Mercury (Hg) slows or completely stops the activity of enzymes . These molecules are inhibitors .
Reaction rate
Enzyme
Enzyme+
inhibitor

21. 7.ACTIVATORS
Some chemicals increase the activity of enzyme and they are called activators
Rate of the reaction
With Activator
Without activator

22. I
K M N + O + M II
By looking at the reaction above, answer the questions.
a. What kind of a reaction is I and II ?
b. Which of them is the enzyme?WHY?
c. Which of them is the product and substrate?

23. H202 H202 H202 Fresh liver Liver grounded Liver boiled
pieces in mortar in water
2 ml of H202 solution is placed in each tube. Fresh , grounded and boiled liver are placed in the tubes as shown in the figure.
a. Write the reaction of equation?
b. Write the correct order of reaction rates from the fastest to the slowest ?
Explain the reasons
H202
H202
H202

24. Enzyme Enzyme Enzyme 3
X Y Z M
As you see in the above reaction, some chemical reactions can ocur in chains. They follow each other. What is the advantage of this working together?
Reactions can be reversible(occur in BOTH ways)
Activation energy is lowered
Reaction speeds up
Types of products increases
Amount of substrate used is reduced. (decreases)