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Chapter 6.3 Notes
Enzymes
I.
Chemical Reactions
A. When bonds are broken and reformed to make different substances.
II.
Chemical Reactions of Life
A. building molecules = ____Synthesis__________
B.
III.
C6H12O6 + 6O2
6H2O + 6CO2
breaking down molecules ___Digestion_____
What is Needed to Start a Chemical Reaction?
Activation Energy
Energy
Absorbed
Making Chemical Bonds =
Storing energy
Breaking Chemical Bonds=
Releasing energy
reactant
Energy
Released
IV.
In the chemical equation below, put
a BOX around the product and
CIRCLE the reactants
products
Nothing Works Without Enzymes
A. all chemical reactions in living organisms require enzymes to work

building molecules __synthesis enzymes_______

breaking down molecules = __digestive enzymes______
What do you think an advantage
would be to lowering activation
energy for chemical reactions within
an organism?
Reactions would happen faster,
like digestion, more efficient, faster
release of nutrients/energy
B. enzymes speed up reactions = _ catalysts____
C. Digestion Reaction
 Is the __breakdown____ of a complex molecule into simpler substances
 These reactions __RELEASE energy____
After digestion reaction, did the
enzyme change or get used up?
NO
D. Synthesis Reaction

The _combining___ of simple molecules into a more complex ones

V.
This reaction _builds new molecules and/or STORES energy___
Enzymes Are Proteins, and each enzyme is the specific helper to a specific reaction
After synthesis reaction, did the
enzyme change or get used up?
NO
A. Each enzyme needs __to be the right shape for the job__
B. Enzymes are named for the reaction they help
i. __Sucrase__breaks down sucrose
ii. proteases breakdown _proteins___
The ending –ase tells you that
something is an _____.
enzyme
iii. lipases breakdown __lipids____
iv. DNA polymerase builds __DNA____
What is the monomer of a protein?
Amino acids
VI.
Enzymes Aren’t Used Up
** Enzymes __are NOT changed by the reaction____
A. __Used only temporary___
B.
C.
Re-used__ again for the same reaction with other molecules
Very little enzyme needed to help in many reactions
VII. Lock & Key Theory
VIII.
A. _Shape of protein__ allows enzyme & substrate to fit
What two factors are most likely to
affect enzyme activity?
B.
Temperature & pH
__Specific enzyme for each specific reaction____
Temperature and the Effect on Rates of Enzyme Activity
A. __Optimum temperature___
i. greatest number of collisions between enzyme & substrate
ii. human enzymes = 35°- 40°C (_body temp = 37 ̊ C_)
B.
Raise temperature (boiling)
i. _Denature protein = unfold = lose shape
C.
Lower temperature
i. molecules move _slower_
ii. fewer collisions between enzyme & substrate
Why is running a high fever so
dangerous?
High fever can begin to denature
proteins and enzymes in body.
Could lead to organ failure,
blindness, death, etc.
Explain what you think would
happen if pepsin was put in an
environment with a pH of 8?
Pepsin would not work or not work
as well due to being out of its ideal
environment.
IX.
pH and the effect on rates of enzyme activity
A. changes in pH changes = ___changes protein shape_____
B.
most human enzymes = _pH 6-8____
i. depends on where in body
ii. pepsin (stomach) = __pH 3___
Enzyme Vocabulary
iii. trypsin (small intestines) = _ph 8__
EnzymeHelper protein that lowers
activation energy for chemical
reactions
SubstrateMolecule that an enzyme acts on
*enzymes are specific
X.
Denature
A. When enzymes are exposed to _extreme pH or high temperatures, they can___
ProductsWhat enzymes help to produce at
the end of chemical reaction
__denature______.
B.
When denatured, an enzyme will ___no longer function _ _, due to a change
__in enzyme structure____.
Active SitePlace on the enzyme where
substrate can attach