Enzymes
Engage
• What happens if the gall bladder is blocked?
• Can you live without a gall bladder?
• What do you think would happen to the
digestive process if your stomach had a
neutral pH?
• What if your stomach had a basic pH?
• If you have an abnormal body temperature,
what do you think the overall affect to
digestion would be?
Explore
• Exploration 1
• A Study of Biochemical Reactions
• You will observe the activity of an enzyme
in two substances, both of which break
down hydrogen peroxide. One substance is
plant tissue, potato. The other is animal
tissue, liver. Both are sources of the
enzyme, catalase, an organic compound.
• Exploration 2
• Toying with Enzymes
Explain
• What is an enzyme?
• A protein that speeds up a chemical reaction
without being destroyed.
• Catalyst
Why do We Need Enzymes?
• Most chemical reactions in the cell take too
long to complete on their own.
• A catalyst (enzyme) is needed to speed up
these reactions.
Enzymes
• Catalytic proteins: change the
rate of reactions w/o being
consumed
• Activation Energy: the E
required to break bonds
• Substrate: enzyme reactant
• Active site: pocket or groove
on enzyme that binds to
substrate
How Do Enzymes Work?
DO NOT WRITE
• Enzymes are used by the
cell to lower the activation
energy needed to start a
chemical reaction.
• This is accomplished by
binding to the reactants.
• They will then twist or
bend the material lowering
the energy needed to split
it.
An Enzyme System
• Active site - specific for
the object it will hold,
called the substrate.
• The enzyme system is the
enzyme and substrate
combined.
Enzyme Reaction
Enzyme Facts
• Enzyme are Proteins.
• DECREASE the activation energy of a
reaction.
• Specific to the substrate they bind.
• Induced Fit Model
• They can be reused.
How Enzymes Work
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Review of Digestive Enzymes
• Why do we need enzymes to help us digest
out food?
– It would take to long without them. They act as
a catalyst to speed up the digestive process.
• What macromolecules to digestive enzymes
act upon?
– Carbohydrate, Lipids, Proteins, Nucleic Acids
• Can you name three digestive enzymes?
Carbohydrate Digestion
• Monomers-small molecules that can be linked to make larger
molecules
• Monosaccharide (single sugar)
• Disaccharide (double sugar)
• MALTASE, LACTASE, SUCRASE
– Enzymes that digest Disaccharides
Fat (Lipid) Digestion
• Bile from gall bladder emulsifies fat.
• LIPASE- enzymes that digests lipids
Protein Digestion
• TRYPSIN and CHYOTRYPSIN – enzymes that
break bonds next to specific amino acids
• Carboxypeptidase – splits off one amino acid at a
time. Works on the carboxyl group.
• Aminopeptidase- works in the opposite direction.
• ENTEROKINASE-hormone that activates these
enzymes.
Elaborate
• Investigating Digestive Process
• Science Kit and Boreal
www.sciencekit.com
• In this lab, you will understand the actions
of different enzymes in your own body.