Transcript chemical reaction

Section 2-4
Chemical Reactions and Enzymes
chemical reaction: a process that changes or transforms
one set of chemicals into another
6CO2 + 6H2O
Reactants
C6H12O6 + 6O2
Products
***Chemical reactions always involve a
change in the bonds that join atoms in
compounds***
Enzymes Speed Up Chemical Reactions By
Lowering The Activation Energy
Activation Energy: The energy
needed to get a reaction
started
Catalyst: speed up the rate of
a chemical reaction by
lowering the activation energy.
Enzymes: proteins that act as
biological catalysts in cells
Enzymes- Special Proteins
• Enzyme- protein that acts as a catalyst
• Catalyst- Speeds up reaction but is not used
up in reaction
• Lowers activation energy
Structure of Enzymes
• Made of Proteins and
a Coenzyme
• Active Site- part of
molecule involved in
reaction
• Substrate- reactant
being catalyzed
Enzyme Activity
Products
Active Site
Enzyme
EnzymeSubstrate
Complex
Enzymes are specific to the
reaction they are involved in
• Enzymes are shaped specifically for the
substrates with which they react
• Act like a lock and key
• Enzymes can be reused, but will
eventually denature
Enzymes are affected by many
variables
• Enzyme effectiveness changes under different
conditions
• Temperature, pH, and enzyme or substrate
concentration all affect how well an enzyme
works
What is pH?
A water molecule can react to form ions
Other molecules can also form ions
pH Scale: an indication of the
concentration of
H+ ions in a solution.
• pH 7: Neutral
• pH <7: Acid
(higher H+ concentration)
• pH >7: Base
(lower H+ concentration)