1. Enzymes The CONTROLLERS of Energy Transformations http://tesladownunder.com /

2. Remember Metabolism… The capacity to acquire & use energy to ensure survival. –Cellular activities, Maintenance, Growth –Building & Accumulating –Breaking Apart & Eliminating Involves… 1.ENERGY 2.CHEMICAL REACTIONS Controlled by ENZYMES

3. Enyzmes Proteins that catalyze chemical reactions –Speed up reactions (“Catalysts”). –Do not become part of the products. Enzymes act on substrates (the specific reactants for a chemical reaction) –Enzymes are substrate-specific. –There are many many enzymes!

4. Enyzmes Active Site – a region (or regions) where the substrate(s) fit.

5. Enyzmes Induced-fit model of enzyme activity. –Enzyme induces the fit of substrates by bringing them into closer proximity & orientation.

6. Enyzmes Enzymes lower the Activation Energy for a particular chemical reaction.

7. Enyzmes Enzymes function best within certain Temperature & pH ranges.

8. Control of Enzymes Inducers (molecules that act as “ON” switches). –Substrates –Cofactors (non-protein portions of an enzyme) Metal ions (Fe ++ ) Coenzymes (large organic cofactors) –Vitamins –NAD + NADH Allow proper enzyme conformation, turning them “ON”.

9. Control of Enzymes Inhibitors (molecules that attach to enzymes, turning them “OFF”) –Competitive Inhibitors Active Site inhibitors (“blockers”) –Non-competitive Inhibitors Allosteric inhibitors Feedback Inhibition –The product of a metabolic pathway inhibits an enzymes responsible for catalyzing a reaction earlier in the pathway.