Download Anaerobic respiration

CELLULAR
RESPIRATION
WITHOUT OXYGEN
Respiration without oxygen is called:
Anaerobic Respiration.
The first part of Anaerobic respiration is the
same as Aerobic :
Glycolysis
Pyruvic
Acid
To the
electron
transport
chain
Glycolysis used 2 ATP
Pyruvic
Acid
To the
electron
transport
chain
Broke into two 3-Carbon molecules called
Pyruvic acid
Glycolysis produced:
2 net ATP’s
(4-2 = 2)
2 NADH
Now if Oxygen is not present, there are two
pathways the pyruvic acid can take:
1. Alcoholic Fermentation
(does not occur in humans!)
2. Lactic Acid Fermentation
1. Alcoholic fermentation
After Glycolysis, you are left with 2 pyruvic
acids, 2 NADH and 2 ATP.
Glycolysis
C C C
Pyruvic Acid
An enzyme “pyruvate decarboxylase” also
attaches to the pyruvic acid causing it to
release a CO2 molecule and leaving a 2 carbon
molecule.
pd
C C C
Acetaldehyde
O
O
NADH gives back 2 high energy electrons to
the pyruvic acid and turns back into NAD+
e e
C C C
NAD
NADH
Then another enzyme (alcohol dehydrogenase)
turns the 2-Carbon molecule into
Ethyl alcohol.
a
h
C C
C C
Ethyl alcohol
Alcoholic fermentation by yeast is the most
familiar form you might know.
Yeast eat the glucose and convert it into
ethanol which is a form of alcohol, and carbon
dioxide…
Beer… is made with yeast who eat the glucose, make
the liquid alcoholic, and the CO2 is the little bubbles
you see in beer.
Yeast is also used in baking not to make
alcoholic bread, but for Carbon dioxide.
The released gas puts small gas pockets
through out the dough causing your bread to
have that holed texture.
So in a chemical equation:
Pyruvic acid + enzymes + NADH → alcohol + CO2 + NAD+
Now let’s look at Lactic acid fermentation
which does occur in your body.
Again we begin just after Glycolysis with the
forming of pyruvic acid. So we start with 2
ATP
Glycolysis
C C C
NADH plus an enzyme (lactate dehydrogenase)
both act on the 3-Carbon pyruvic acid.
e e
C C C
ld
NAD
NADH
This causes the 3-Carbon molecule to
chemically change into a 3-carbon molecule
called “Lactic Acid” C C C
So chemically:
Pyruvic acid + enzyme + NADH → Lactic Acid + NAD
When running hard, you normally do not breathe
enough oxygen to keep up with the demand that your
muscles are asking for.
Since there is limited oxygen, your muscles start to
produce ATP through lactic acid fermentation.
This acid starts to cause a burning sensation over
your muscles.
When using your muscles during some form of
exercise…you ever get a cramp?
What has happened is that the
pyruvate in the muscle has to
feed the muscle without oxygen
You are pushing yourself as hard as you can….
So because the muscles themselves are using up most
of the oxygen, your body converts pyruvate into
lactate to get you ATP to continue..
After a short period of time you muscles start to
hurt. This is because the lactic acid has built up so
much on your muscles…you cramp in pain.
So how do you get rid of the lactic acid on your
muscles then?
Oxygen! You need to breathe to break down the
lactic acid, so many athletes inhale pure oxygen
afterwards…
You , just rest and breathe real hard…
So what method is best?
-Cellular respiration for energy OR
- lactic acid fermentation.
For quick burst of energy “fight or flight”
reflex you normally use lactic acid
fermentation.
For most others, you use cellular respiration,
but it releases energy more slowly, so you tend
to pace yourself over longer times so you won’t
cramp up or become too exhausted.
Comparing Photosynthesis & Cellular Respiration
PHOTOSYNTHESIS
Function
Energy Capture
CELLULAR RESPIRATION
Energy Released
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 (glucose) and O2
Products
C6H12O6 (glucose) and O2
CO2 and H2O
Equation
6 CO2 + 6 H2O → C6H12O6 + 6 O2
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Energy
Creature
Plants, algae, some bacteria
Energy
Animals, some bacteria
VOCABULARY !
Anaerobic Respiration
Alcoholic Fermentation
Pyruvate decarboxylase
Ethyl alcohol
Lactic Acid Fermentation