1. The “dirty dirty” on biological catalysts.
Enzymes
The “dirty dirty” on biological catalysts.

2. Vocab: Reactant: Product: The starting material in a reaction.
similar to “ingredients” in a recipe.
Usually on the left side of the reaction.
Product:
What is produced (made) at the end of the reaction.
Usually on the right side of the reaction.

3. Example: Glucose + O2  CO2 + H20 What are the reactants?
Glucose and O2
What are the products?
CO2 and H20

4. With your neighbor:
Figure out the reactants and products for the following reactions:
H2O2  H20 + O2
NaOH + HCl  NaCl + H20

5. What is a catalyst?
Anything that speeds up a chemical reaction.

6. What is an enzyme?
A protein that acts as a catalyst in living organisms.

7. How do enzymes speed up chemical reactions in cells?
By lowering the activation energy for the reaction.
The WHAT???
The activation energy. It is the amount of energy that must be absorbed by the reactants for the reaction to start.
General rule: the higher the activation energy, the harder it is to do the reaction.

8. Substrate
This is the molecule being changed by the enzyme-catalyzed reaction (it is the reactant in the reaction).
Each specific enzyme is shaped so that it can bond (connect) with only one type of molecule (substrate). (L&K/IF)
The place on the enzyme where the substrate bonds is called the Active Site.

9. Enzyme-substrate complex
This “fancy” term is simply used to describe the interaction between an enzyme and a substrate.
Don’t think of “complex” as “hard/difficult”; instead think of it as “a structure made of different parts.”

10. Example of Enzyme-Substrate Complex in Action:

11. See page 77 in your textbook for a picture of the Enzyme-Substrate Complex

12. Do enzymes always work? NO!!! They can be inactivated (denatured) by:
pH changes
High temperatures (above normal body temperature.)
Salty environments

13. So…why are high fevers so dangerous?
The high temperatures will break down the proteins in your body, including the enzymes.

14. Water, water everywhere…
What’s so important about this stuff anyway?

15. Water is a “Polar Molecule”
“Polar”, in this meaning, does NOT mean “cold”
Polar means the electrons in the molecule are shared unequally between the atoms.

16. - Water: Red = O2 Blue = H2 + +
The red oxygen molecule is bigger, therefore it can pull on the hydrogen molecules more then the hydrogens can pull on it.

17. So what?
This allows water molecules to connect to each other VERY closely.
They connect through hydrogen bonds.
Bonds between the hydrogen of one molecule and the oxygen of another molecule.

18. Cohesion The attraction between molecules of the same substance.
Ex: water to water.
This attraction is due to hydrogen bonds.
Cohesion is how trees get water from their roots to their leaves.

19. Adhesion The attraction between molecules of different substances. Ex:
water in a graduated cylinder.
Trees getting water from the roots to the leaves.

20. Important characteristics of water:
1.) In its solid form, water is less dense
than its liquid form.
2.) Water can absorb a great amount of
heat without turning into a gas.