Transcript Cellular Respiration

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Cellular
Respiration
Cellular Respiration

The process by which the mitochondria
breaks down glucose to produce ATP is
called cellular respiration.
C6H12O6
+ 6O2  6CO2 + 6H2O
Cellular Respiration
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
When the body has oxygen, aerobic
respiration can take place and produce
36 ATP molecules.
There are 3 stages of aerobic
respiration:
 Glycolysis
 Citric acid cycle (aka Krebs Cycle)
 Electron transport chain
Glycolysis

Glycolysis takes place in the cytoplasm of
the cell.
Glycolysis Products
2 Pyruvate produced
Pyruvic acid
Glycolysis

Glycolysis is the process where glucose is broken
down in 2 pyruvic acid molecules. Pyruvic acid is a
3 carbon molecule.
4
-2
2

The net gain of ATP molecules in glycolysis is 2 ATP
molecules.
Glycolysis

Following glycolysis, the pyruvic acid moves
into the mitochondria.
The Citric Acid Cycle




AKA
Kreb’s cycle
The Kreb’s cycle takes place in the MATRIX!
Pyruvic acid enters the citric acid cycle and
becomes broken down. As this occurs, 2
carbon dioxide molecules are released.
In addition, 2 ATP molecules are released.
Electron carriers such as FAD and NAD are
used to pick up energized electrons and
pass them to the ETC.
Citric Acid Cycle
Electron
carriers
FYI: Flavin adenine dinucleotide
Nicotinamide adenine dinucleotide
The Electron Transport Chain
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The last step of respiration is the electron
transport chain or ETC.
It takes place in the inner membrane space.
In the presence of oxygen, the electron
transport chain will produce 32 ATP
molecules and water.
The total of ATP molecules released from
AEROBIC respiration is 36.
Electron Transport Chain

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Electron carriers NADH and FADH2 release the Hydrogen ions
across the membrane. This creates a concentration gradient.
When oxygen enters the ETC, it becomes the final electron
acceptor of the Hydrogens and creates H2O.
As the hydrogen ions come back across the membrane, ADP is
converted into ATP.
Animation: http://www.science.smith.edu/departments/Biology/Bio231/etc.html
Electron Transport Chain

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Electron carriers NADH and FADH release
the Hydrogen ions to proteins to cross the
membrane. This creates a concentration
gradient.
When oxygen enters the ETC, it becomes
the final electron acceptor of the Hydrogen
ions and creates H2O.
As the hydrogen ions come back across the
membrane, ADP is converted into ATP.
THE BIG PICTURE
Cellular respiration
Anaerobic Respiration
AKA
Fermentation
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There are times when cells are without
oxygen for a short period of time. When this
happens, anaerobic respiration is taking
place.
In anaerobic respiration, glycolysis takes
place; then followed by one of two pathways:
 Lactic Acid Fermentation or
Alcoholic Fermentation.
Total ATP molecules released = 2.
at
io
n
Fe
rm
en
t
Anaerobic:
absence of
oxygen
Aerobic:
presence
of oxygen
Types of Anaerobic Respiration

When our cells run out of oxygen and begin
fermentation, we build up lactic acid. That
lactic acid build up in the muscle makes us
feel a cramp.
C6H12O6  ATP + lactic acid
fermentation
Types of Anaerobic Respiration
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Some bacteria also undergo fermentation.
They release ethyl alcohol and carbon
dioxide.
C6H12O6  ATP + CO2 + ethyl alcohol
This process is key for the bacteria that
create wine and apple juice.
fermentation
Types of Anaerobic Respiration

Yeast also undergo this type of fermentation
when making bread.
Comparing Photosynthesis and Respiration
• Glucose made
• Light energy required
•ATP broken down in 2nd
phase of p.s.
•CO2 taken in
•O2 released
•Needs water
•Takes place in
chloroplast
•Takes place in
autotrophs
•Glucose broken down
•Light is not required
• Energy created in ATP
•CO2 released
•O2 taken in
•Water released
•Takes place in
mitochondria
•Takes place in all
organisms
•Require use of ATP molecules
•Take place in plants
•Necessary to sustain all life on earth