Enzymes Kathryn Blair, M.S. BIO 101 Core Concepts May be used for educational purposes only

Basic Definitions Metabolism: All chemical reactions in a cell Reactant: Start; change or combine Product: Result from reaction Catalyst: Speeds up reactions Enzyme: Catalyst body reactions

REACTANTS PRODUCTS CO2+ H2O H2CO3 (carbonic acid)

How does an enzyme work? ENZYME has an ACTIVE SITE that SUBSTRATE (reactant) must perfectly fit into. Enzyme: Lock; Substrate: Key

The Substrate must perfectly fit the Active Site of the Enzyme to work.

Enzymatic reactions are much faster Enzymes are not used up in the reaction

It is like a discount on the cost of the reaction Enzymes reduce the energy needed for reaction to occur (energy of activation) It is like a discount on the cost of the reaction 100 50

Denaturing: extreme temperature and pH can change enzyme shape, rendering it useless. NORMAL SHAPE DENATURED SHAPE

Reaction Speed Affected by: Temperature Concentration pH ACID 7 BASE

Temperature Effect on Enzymes What does heat usually do to reactions? Speed up Cold? Slow down What temperature should human body enzymes work best at? 37o Celsius

pH Effect on Body Enzymes Where would an enzyme that worked best in acidic conditions be located? Stomach Basic conditions? Pancreas Neutral conditions? Blood and CSF (7.4), cytoplasm (7.2)