Review the Quiz!!
What is the monomer of a
Carbohydrate?
What is the POLYMER of a
Carbohydrate?
Details on Carbohydrates
• How are they used?
– QUICK energy
– Structure (cell wall =
CELLULOSE)
– Storage (Apples, Potatoes =
STARCH)
– Converted to LIPID if NOT
used by animal for energy
What’s the difference between a
carbohydrate and a lipid?
Sucrose has a 1:2:1
ratio of C:H:O
• Count the
HYDROGENS!
This is NOT true for a lipid!
What are the Monomers of
Lipids?
What are the POLYMERS of
LIPIDS?
Phospholipid and Triglyceride
Each is a
glycerol +
some fatty
acids…
How many fatty
acids are there
in each?
Details on Lipids
• Which are healthier, SATURATED or
UNSATURATED fats?
Saturated vs. Unsaturated
Which can I pack more of into a
recycling bin, flat paper or
crumpled paper?
Details on Proteins
• 5 Types
– Enzyme (Digestion
– Transport (Blood Oxygen)
– Hormone (Insulin, etc)
– Structural (Hair, Bone)
– Contractile (Muscle)
Thursday Quiz 
1. What are the 4 types of organic
molecules?
2. What is an enzyme?
3. How can our cells naturally make a toxin
like Hydrogen Peroxide and we are still
alive?
Biology I
Ch 2.4 Chemical Reactions
and Ch 2.5 Enzymes
Essential Question:
Why are enzymes important to
living things?
SC Biology Standard: 3.5 & 2.8
Let’s Talk about Reactions!
What is a reaction?
A Chemical Equation
On the left side:
REACTANTS
On the right side:
PRODUCTS
Examples:
Oxygen, Water, and
Sun
Examples:
Carbon Dioxide and
Glucose
Activation Energy
• Activation Energy – Energy that is needed
to start or “activate” a chemical reaction.
Enzymes
• Enzymes – Proteins that
act as biological catalyst.
– Catalyst speed up chemical
reactions
• They work by lowering the
activation energy.
• Enzyme names usually
end in –ase.
Enzymes
Work by lowering the
activation energy.
Enzyme names
usually end in –ase.
Examples:
– Protease, Lipase,
Lactase, Peroxidase
With a Buddy:
• What do you think each of these breaks
down?
– Protease - _________________
– Lipase - _________________
– Lactase - _________________
– Peroxidase - _________________
The Enzyme Reaction
3 stages:
1. They MEET
2. They BIND together
3. They LEAVE
Now, Let’s put these into BIOLOGY terms
TOGETHER.
The Enzyme Reaction
• Substrates – The reactants of the
reaction that “Meet” the ENZYME
– Substrates bind to the active site temporarily.
– It fits perfectly, like a “lock & key model”
The Enzyme-Substrate Complex
• This is what it’s called when the ENZYME
and SUBSTRATE BIND together.
• Let’s see the animation!
http://highered.mcgraw-hill.com/sites/dl/free/0072495855/291136/enzymes.swf
The Products
• The ENZYME leaves UNCHANGED!! It
will ALWAYS be able to work AGAIN.
– If I take the bubbly potato out, rinse it off and
add MORE hydrogen peroxide, the potato
enzymes will bubble up AGAIN and AGAIN
and AGAIN
• The SUBSTRATE leaves and is
CHANGED! It can no longer react.
The Enzyme-Substrate Complex
Enzyme’s Lock & Key Model
Only certain
SUBSTRATES fit
SPECIFIC ENZYMES
Enzyme’s Reaction Rates
• ↑ amount of enzyme = ↑ reaction rate
• ↑ amount of substrate = ↑ reaction rate
• Maintain optimal pH = ↑ reaction rate
– Any other pH slows reaction rate down
• ↑ in temp = ↑ reaction rate*
*only to a point, after which the
enzyme is said to be denatured
(burnt) & no longer functions