1. III. Enzymes

2. A. Structure 1. Enzyme is considered a lock
2. ATP supplies energy
a. Because ATP is reacted with the reactant it is called a coupled reaction

3. B. Coenzymes
1. Often times energy from one reaction is transferred to be used by a different reaction
a. This is a coenzyme
2. Most important is NAD+ (nicotinamide adenine)
a. Gets a hydrogen with high energy electrons and becomes NADH

4. C. Enzymes directing metabolism
1. Concentration of enzymes can be increased or decreases depending on needs
2. Different cells contain different enzymes depending on job
3. Signal molecules can change enzyme shape
a. Called allosteric enzymes
b. Lets enzyme release or prevent binding