Metabolism:
Energy and Enzymes
Chapter 6
LAB
Tues 9/16
*next week! Be there!
Lab 136
http://www.calstatela.edu/univ/ppa/
campus_map.pdf
Biological
Science
building
room 136
-13 on map
extra 5 min to get
there
Quiz Next Time
macromolecules
http://www.lachsa.net/apps/pages/i
ndex.jsp?uREC_ID=383647&type
=u&pREC_ID=507658
Energy = the ability to do work
Kinetic Energy (energy of motion)
Potential Energy (stored energy)
http://youtube.com/v/Jnj8mc04r9E
First Law of Thermodynamics - the law of conservation of
energy (not created or destroyed)
Second Law of Thermodynamics - energy cannot be
changed without a loss of usable energy (heat)
QOD
Staple/tape is the graphic organizer as
last QOD
Today:
• What are the 4 shapes of proteins?
Draw a small sketch to go with your
explanation or each shape
MATCHING
a. carbohydrate
c. protein
1.
2.
3.
4.
5.
6.
7.
b. lipids
d. nucleic acids
contains adenine and thymine
lactose
chains of amino acids
long term energy storage
cholesterol
chains of fatty acids and glycerol
plant cell walls
Chemical Reaction
 Reactants: starting substances, on the left side of
the arrow.
 Products: substances formed during the reaction,
on the right side of the arrow.
Baking soda + vinegar
Reactants
water + CO2
Products
What are the reactants and products?
6CO2 + 6H2O
C6H12O6
Reactants
Products
HO
H O+ O
2
2
Reactants
2
2
Products
http://www.youtube.com/watch?v=Fz9eV-EWtpY
Metabolic Reactions
Reactants --> Products
Exothermic - releases
energy
Endothermic = absorbs
energy
Chapter 6
Chemistry in Biology
 This reaction is
exothermic and
released heat energy.
 The energy of the
product is lower than
the energy of the
reactants.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
This reaction is
endothermic and
absorbed heat
energy.
 The energy of the
products is higher
than the energy of
the reactants.
Metabolic Pathways & Enzymes (6-3)
Enzyme - protein molecule that functions as an organic
catalyst to speed reactions
Substrate - reactants in the enzymatic reaction, this is what an
enzyme attaches to
Activation Energy- the energy required to cause the reaction
Chemistry in Biology
Energy of Reactions
activation energy:
the minimum
amount of energy
needed for a
reaction.
Enzymes lower the
activation energy
Properties of Enzymes:
•Enzymes are made of
proteins.
•They speed up
chemical reactions
inside the cytoplasm.
They are needed only
in small amounts
They remain
unchanged after each
reaction and can
therefore be reused
Each enzyme is
specific for a substrate
•
•
•
Chapter 6
Chemistry in Biology
Substrates: reactants that bind to the
enzyme
active site: specific location where a
substrate binds on an enzyme
Lock and Key Model
Each enzyme acts on a specific substrate
Induced Fit Model - substrates and enzymes fit together
like a lock and key.
Degradation vs Synthesis
breaking down vs building
Factors Affecting Enzymatic Speed
1. Substrate concentration
2. Temperature & pH *
3. Enzyme concentration
Enzymes can be denatured - they change shape so much that they are no longer
effective. High temp or pH can cause denaturation.
Siamese cats have an enzyme that works at lower
temperatures only, causing the nose and ears to
become a darker color than the rest of the body.
Enzymatic Inhibition - when
a substance binds to an
enzyme and decreases its
activity. (Usually reversible) Inhibited:
Competitive Inhibition
vs.
Noncompetitive Inhibition
(allosteric site)
**Both are forms of
feedback inhibition
http://youtube.com/v/PILzvT3spCQ
Normal
Some inhibitors are NOT reversible - poisons like
cyanide, lead poisoning all affect enzymes
QUESTION: What type of inhibition is pictured below?
Enzyme Animation (Tutorial)
http://www.stolaf.edu/people/giannini/flashanimat/enzymes/pro
x-orien.swf
Enzyme Quiz
http://www.sciencegeek.net/Biology/review/U2Enzymes.htm
Enzyme Lab
2H2O2 ----> 2H2O + O2
Hydrogen Peroxide is broken down by the
enzyme catalase within cells.
Potatoes hold the enzyme catalase, which
will speed up the breakdown of hydrogen
peroxide
Proteins have four
shapes
1. Primary Structure sequence of amino acids that
form the polypeptide chain
2. Secondary Structure Parts of the polypeptide fold
into local patterns (alpha
helix or pleated sheet)
3. Tertiary Structure - the
overall 3D shape (globular or
fibrous)
4. Quaternary Structure consists of two or more
polypeptide chains or
subunits
Factors Affecting Enzymatic Speed
1. Substrate concentration
2. Temperature & pH *
3. Enzyme concentration
Enzymes can be denatured - they change shape so much
that they are no longer effective. High temp or pH can
cause denaturation.
The activity of
catalase can be
seen by the
bubbling of oxygen
during the reaction
Generally speaking,
catalase reactions occur
faster at warmer
temperatures.
If temperature is too hot
(boiling) then the
enzyme becomes
denatured
Enzymatic Inhibition - when
a substance binds to an
enzyme and decreases its
activity. (Usually reversible) Inhibited:
Competitive Inhibition
Noncompetitive Inhibition
(allosteric site)
**Both are forms of
feedback inhibition
http://youtube.com/v/PILzvT3spCQ
Normal
Both cofactors and coenzymes help to complete
the structure of a conjugated enzyme
CO-ENZYME is a small organic non-protein MOLECULE that
carries chemical groups between enzymes while a
ex: iron, magnesium or zinc.
CO-FACTOR is a non-protein CHEMICAL COMPOUND that
is bound tightly to an enzyme and is required for catalysis.
ex: NAD+, NADP+ and FAD+
Virtual Labs with Enzymes
McGraw Hill Lab
Bio 114 Enzymes
Lab Bench Enzyme Catalysis
ATP
Add
energy
ADP
release
energy
Ribose
(sugar)
Diphosphate
Energy stored in ATP is released by breaking
the bond between the 2nd and 3rd phosphates
ATP
Energy stored in ATP is released
by breaking the bond between the
2nd and 3rd phosphates.
2 Phosphate groups
P
ADP
Copyright Pearson Prentice Hall
ATP - the energy
currency of cells
(adenosine triphosphate)
Functions:
1. CHEMICAL WORK Supplies energy needed
to make macromolecules
that make up the cell (and
organism)
2. TRANSPORT WORK Supplies energy needed
to pump substances
across the cell membrane
3. MECHANICAL WORK
- supplies energy needed
to make muscles contract
and other cellular parts to
move (flagella)
How do cells make ATP?
• Cellular respiration
• Photosynthesis
• Electron transport chain
Chemiosmosis= production
of ATP due to hydrogen ion
gradient across a
membrane
ATP
Review videos
https://www.youtube.com/watch?v=ok9esggzN18
https://www.youtube.com/watch?v=5GMLIMIVUvo