Download What is Energy?

ENZYMES and
Activation Energy
EQ: How do enzymes affect
a reaction?
What is Energy?
• Energy is the ability to cause
matter to move or change.
• All life processes are driven by
energy
• Where does all energy come from?
Chemical Reactions
• When bonds are broken and
reformed to make different
substances, energy is released.
EX:
Reactants
Products
C6H12O6 + 6O2
6CO2 + 6H2O
What is Metabolism?
• Metabolism is the sum of all
chemical reactions in your body
- Metabolism is basically two
components
1.
2.
Breaking down foods for energy
Building new compounds to make
new products
Activation energy
What is needed to
start a reaction?
Activation Energy is
the energy needed to
break down reactants
into products.
reactant
Energy released
Products
What is a Catalyst?
• A catalyst is anything that lowers
activation energy.
• Enzymes are organic catalysts.
•Predict what the graph will look like
after a catalyst (enzyme) is added.
What do you notice about
the activation energy?
reactant
Products
Comparing Reactions
Energy released
Energy absorbed
Which line would represent a
reaction without an enzyme
present?
With an enzyme present?
Reactant
Products
Enzymes lower the amount
of activation energy needed
How Do Enzymes Work?
• Enzymes work
like a lock and
key.
• Specific
enzymes have an
ACTIVE SITE for
specific
substrates.
enzyme
substrate
How Do Enzymes Work?
1. Each substrate fits into the
enzyme’s active site.
2. Then the enzyme controls
the rate of the chemical
reaction.
3. The substrate is broken into
products.
4. The enzyme is free to accept
another substrate.
Enzymes are NEVER used
up in a reaction!!
the reaction rate is
controlled by enzymes
Denaturation

A protein is denatured when it
loses its shape and becomes
inactive.
Enzymes can be affected by:
• Temperature:
Battery
Acid
• pH:
0
Blood
(7.5)
3
5
7
Neutral
• Concentration:
Bleach
9
11
13
Inhibitors
Competitive
Inhibition
Occurs when a
molecule mimics the
substrate and enters
the active site, not
allowing the real
substrate to fit.
Non-competitive
Inhibition
Occurs when a
molecule binds to an
enzyme somewhere
other than the active
site, causing a change
in shape.