1. Chemical Reactions
And Enzymes

2. Chemical Reactions
Processes that change one set of chemicals into another set of chemicals
Reactants  Products
(bonds break) (new bonds form)

3. Energy in Reactions Some reactions release energy -often spontaneously
Some reactions absorb energy
-need an energy source
What significance do these energy changes have for living things?

4. Activation Energy
The energy needed to start a reaction

5. Enzymes
Some reactions are too slow or have activation energies that are too high
Catalyst – a substance that speeds up the rate of a chemical reaction

6. ENZYMES (proteins) act as biological catalysts
They speed up chem.rxns. inside cells by lowering the activation energy
They are very specific (catalyze 1 rxn.)

7. Enzyme Action Reactants need enough energy for bonds to break
Enzymes provide a site where reactants can be brought together to react (active site)
The site reduces the energy needed
Substrates -the reactants of enzyme-catalyzed reactions (ex. Hexokinase, pg )

8. Enzyme-Substrate complex

10. Enzyme Activity
Enzymes can be affected by any variable that influences a chemical reaction. Denatured
examples: pH, temperature change
Enzymes in human cells work best at 37°C (normal body temp.)
Lew-port enzymes

11. Cells have proteins that help turn enzymes on and off
Enzymes are important in:
-regulating chemical pathways
-making materials that cells need
-releasing energy
-transferring information
-forming tissues
-fighting disease

12. Hydrolysis of Gelatin
Proteases-enzymes that break down other proteins into smaller polypeptides, amino acids
Isolated from strains of Bacillus bacteria
-stable at High Temp
-can be genetically engineered

14. Stable at alkaline pH, various temps.
Added to laundry detergents
Can be genetically engineered

15. http://http://homepage. smc