1. ENZYMES

2. Enzymes are special proteins. Enzymes are made on ribosomes.
Enzymes are called
organic or biological
catalysts
Ribosome
Catalysts speed up a reaction but are not used up in the reaction.

3. Do humans need enzymes?

4. YES!

5. Enzymes are used in digestion to give our body energy.

6. Each enzyme has a unique shape
Enzymes have a complex folded shape. Each type of enzyme is folded differently. So enzymes that help to break down milk have one shape and enzymes that help break down proteins have a totally different shape.

7. ENZYMES SPEED UP REACTIONS BY LOWERING THE ENERGY NEEDED
Mountain climbers need a lot of energy to make it over the mountain. The bigger the mountain, the more energy that is required.

8. Just like Mountain Climbers, a certain amount of energy is required for a chemical reaction to take place. Adding Enzymes lowers the amount of energy needed.
Reaction with enzyme
Reaction without enzyme
**The blue arrows represent the amount of energy required.

9. How do enzymes work?
Substrate: the substance that attaches to the enzyme and is acted on by the enzyme
Active Site: The place on the enzyme that connects to the substrate.
The active site of the enzyme connects to the substrate and forms one or more products.

10. This enzyme is working to split apart one substrate into two products
This enzyme is working to split apart one substrate into two products. Some enzymes work the opposite way and several substrates bind at the active site to form one product.
Substrate
Products
Active site
Enzyme
Enzyme
Enzyme
Enzyme

11. Lock and Key Enzymes are specific
This means that only one type of substance,
or substrate, will fit into each enzyme.
Just like your house key only
works at your house.
Induced fit

12. Lock and Key The key to your house can open your door many times.
An enzyme can also be used over and over again.
A key fits a specific place on a door.
Just as the substrate binds to a specific place on
the enzyme called the active site.

13. Just as humans have an optimal body temperature, enzymes only work at a particular temperature.

14. Effect of heat on enzyme activity
If you heat an enzyme above its optimal temperature, bonds break .
The optimal temperature is the temperature at
which the enzyme works best.
When bonds break, the enzyme loses its folded up
structure and changes shape
This is called denaturing the protein. Denaturing changes the shape of the enzyme so the substrate no longer fits.
(If you melt the lock, the key will no longer fit)

15. Denatured enzymes When an enzyme is denatured, its shape is changed.
Changes in temperature and pH can cause changes in the shape of the enzyme.
When the shape of the enzyme is changed and the substrate will no longer fit, the enzyme does not work any more.
Substrate will not fit the shape of the enzyme
High temperature or wrong pH changes shape of enzyme.