DO Now
• What is the photosynthesis
formula?
• 1. What are the stages of cellular respiration?
• 2. What are the difference between aerobic
and anaerobic respiration?
Energy needs of life
• Animals need energy for…
•
•
•
•
•
synthesis (building for growth)
reproduction
active transport
movement
temperature control (making heat)
Where do we get energy?
• Energy is stored in organic molecules
– carbohydrates, fats, proteins
• Animals eat these organic molecules  food
– digest food to get
• fuels for energy (ATP)
• raw materials for building more molecules
– carbohydrates, fats, proteins, nucleic acids
ATP
What is energy in biology?
ATP
Adenosine TriPhosphate
Whoa!
HOT stuff!
2009-2010
Releasing the Energy (Break the Bond)
• Break ATP into ADP
and P to release energy!
• ADP—adenosine diphosphate
Harvesting energy stored in food
• Cellular respiration: the process of
breaking down food to produce ATP
• in mitochondria
• using oxygen
food
– “aerobic” respiration
– usually digesting glucose
• but could be other sugars,
fats, or proteins
O2
glucose + oxygen  energy + carbon + water
dioxide
C6H12O6 +
6O2
 ATP + 6CO2 + 6H2O
ATP
What do we need to make energy?
• The “Furnace” for making energy
– mitochondria
• Fuel
– food: carbohydrates, fats, proteins
• Helpers
– oxygen
– enzymes
Make ATP!
Make ATP!
All I do all day…
And no one
even notices!
food
• Product
enzymes
– ATP
• Waste products
– carbon dioxide
• then used by plants
– water
O2
ATP
CO2
H2O
Mitochondria are everywhere!!
animal cells
plant cells
How do we use ATP to do work?
Can’t store ATP
 too unstable
 only used in cell
that produces it
 only short term
energy storage
carbohydrates & fats
are long term
energy storage
Whoa!
Pass me the
glucose & oxygen!
ATP
Adenosine TriPhosphate
Adenosine DiPhosphate
ADP
A working muscle recycles over
10 million ATPs per second
work
The Steps of Respiration
• 1. Glycolysis (no oxygen required)
• 2. Kreb’s Cycle (oxygen required)
• 3. Electron Transport Chain (oxygen required)
Glycolysis
• Convert glucose  pyruvate
• Occurs in the cytoplasm
• Produces 2 net ATP
Kreb’s Cycle
• Occurs in the mitochondria
• Produces CO2
• Produces 2 net ATP
per cycle
Do Now
• What are the reactants and
products of respiration?
Electron Transport Chain (ETC)
• Occurs in the mitochondria (inner membrane)
• requires OXYGEN
• Produces 32 net ATP
ETC
• ATP Synthase: enzyme that
produces ATP (from ADP +
P) when protons pass through
(passive transport)
• Proton gradient allows this to
occur—as electrons travel
down the ETC, protons are
forced into the intermembrane
space (active transport)
• OXYGEN is the final electron
acceptor—produces H2O
ATP
How much energy are we
talking?
Cellular respiration produces a
net total of 36
!
ATP
Glycolysis
Kreb’s Cycle
ETC
2
2
32
Total
36
ATP
ATP
ATP
ATP
What if oxygen is missing? O2
• No oxygen available = can’t complete
aerobic respiration
• Anaerobic respiration
– also known as fermentation
• alcohol fermentation
• lactic acid fermentation
– no oxygen or
no mitochondria (bacteria)
– can only make very little ATP
– large animals cannot survive
yeast
bacteria
Anaerobic Respiration
• Fermentation
– alcohol fermentation
• yeast
– glucose  ATP + CO2+ alcohol
– make beer, wine, bread
– lactic acid fermentation
• bacteria, animals
– glucose  ATP + lactic acid
– bacteria make yogurt
– animals feel muscle fatigue
Tastes good…
but not enough
energy for me!
O2
Do Now
Write down the stages of cellular
respiration and the amount of ATP
produced at each stage
Glycolysis
Kreb’s Cycle
ETC
2
2
32
Total
36
ATP
ATP
ATP
ATP
Aerobic v.
Anaerobic
Respiration
Balloon and Yeast Demo
• Fact: Yeast undergo
respiration
• PREDIT: What will happen to
the balloon when I mix yeast
and sugar in warm water?
• ANALYZE:
• 1. Why did the balloon swell
up?
• 2. Why did I add sugar to the
yeast?
What happens when we
DON’T have O2??
Definition: a form of Cellular Respiration
that occurs when O2 is absent or scarce.
A.k.a. fermentation
Fermentation allows
glycolysis to continue
Note: Fermentation itself
does not produce ATP—it
allows glycolysis to
continue, which produces 2
ATP
Anaerobic Respiration:
WHERE does it occur?
Anaerobic Respiration: 2 Versions
Lactic Acid Fermentation
Alcohol Fermentation
• Produces…
• Produces…
– Lactic acid (C3H6O3)
• Occurs during highintensity exercise
• Occurs in your muscle
cells
• Also in bacteria and fungi
– Ethanol
– CO2
• CO2 accounts for the
carbonation (the
bubbles!)
• Occurs in yeast and in
bacteria
Lactic Acid Fermentation
Let's hear from the Dr.’s
Alcohol Fermentation
Other effects of fermentation
STOP AND THINK
• Why do you use yeast to make bread dough rise?
• Why does it make sense that
bacteria in your digestive tract
undergo fermentation?
Guess Who?: Fermentation Edition
Guess Who??
• 1. occurs in this organelle:
• 2. can occur in the absence of O2
Guess Who??
• 3. occurs here:
• 4. produces CO2 as a product
• 5. produces ~36 ATP
Guess Who??
• 6. Accounts for the burn you feel in your
muscles when you exercise
• 7. Can make beer
• 8. Involves the ETC
• 9. Is much less energy-efficient
• 10. O2 is the final electron acceptor
• 11. Allows glycolysis to continue.
Group Activity (~10 minutes)
• Create a concept map in your groups
using the notecards provided! Fill in
yourself the appropriate # of ATP
molecules.
Glucose
Glycolysis(cytosol)
O2 Present
Aerobic
Respiration
~36 ATP
CO2
No O2 Present
Lactic Acid
Fermentation
2 ATP
Lactic
acid
Alcohol
Fermentation
2 ATP
Ethanol
CO2
Exit Slip
• How do we differentiate between Aerobic
and Anaerobic Respiration? Provide at
least 3 reasons.