ENZYMES and
Activation Energy
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
• Occurs when bonds are broken
and reformed to make different
substances.
EX:
Reactants
Products
CO2+H20
H2CO3
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 you
• Literally, you are
what you eat!
What is needed to
start a reaction?
reactant
Products
What is a Catalyst?
• A catalyst is anything that lowers
activation energy
There are basically two kinds:
1. Organic
2. Inorganic
• Organic catalysts are called Enzymes
Why is the activation
energy lower?
reactant
Products
Comparing Reactions
Which line would
represent a reaction
without an enzyme
present?
With an enzyme
present?
Reactant
Products
How Do Enzymes Work?
• Enzymes work
like a lock and
key.
• Specific
enzymes work
with specific
substrates.
enzyme
substrate
How Do Enzymes Work?
• Each substrate fits
into the enzyme’s
active site.
• Then the enzyme
controls chemical
reaction.
Enzymes can be affected by:
• Temperature:
Battery Acid
• pH:
0
Blood (7.5)
3
5
7
Neutral
• Concentration:
9
Bleach
11
13
All Cells Need Energy
•Cells need energy to do a variety of
work:
Making new molecules.
Building membranes and
organelles.
Moving molecules in and out of the
cell.
Movement.
Where Does A Cell Get
Energy?
• Food is broken down to a form
the cell can use.
• Extra energy is stored in an ATP
molecule, a nucleotide.
What Is ATP?
• ATP – adenosine triphosphate is
a molecule made up of an
adenine, ribose, and 3 phosphate
groups.
Adenine
Ribose
How Does ATP Work?
• Energy is stored in the bond between
the second and third phosphate
group.
• When the bond is broken, energy is
released and ADP is formed.
Adenine
Ribose
ATP – Energy Currency
• Within a cell, formation of ATP from
ADP and phosphate occurs over
and over, storing energy each time.
• As the cell uses energy, ATP
breaks down repeatedly to release
energy and form ADP and
phosphate.
ATP stores Energy
• ATP is the special carrier molecule that
stores energy available for cell use.
energy
P
ATP
ADP
energy
P
• ATP is the energy currency of the cell;
the energy source for all cell functions.
Making Energy
• Cells make energy in two ways:
–Photosynthesis – takes place in
the chloroplasts.
–Respiration – takes place in the
mitochondria.