1. Fermentation
Section 9.3

2. Glycolysis Glycolysis can generate energy when oxygen isn’t available
BUT, in a few seconds all of a cell’s NADP+ ions are full of electrons
No oxygen means no electron transport chain
Without NADP+ glycolysis stops
Fermentation saves the day…..

3. Fermentation
Cells convert NADH to NAD+ - high energy electrons are passed back to pyruvic acid
Glycolysis can continue happening
Fermentation is anaerobic – occurs in cell cytoplasm
Two types
Alcoholic fermentation
Lactic acid fermentation

4. Alcoholic fermentation
Yeasts and some other microorganisms use alcoholic fermentation to produce ethyl alcohol and carbon dioxide
Used to make bread rise, used to make alcohol

5. Lactic acid fermentation
Most organisms can perfrom lactic acid femernattion
No carbon dioxide is given off
Lactic acid from bacteria can be used to make cheese, yoghurt, sour cream
Acid = sour taste
Humans produce lactic acid
Muscles are most adapted to do this, as they often need large supplies of ATP

6. Energy and exercise Humans have three sources of energy for sports
ATP already in muscles
Enough for a few seconds
ATP made by lactic acid formation
Enough ATP for 90 seconds (200 – 400 meter sprint…)
Large amounts of lactic acid builds up, an oxygen debt that must be repaid

7. Energy and exercise continued
ATP made from cell respiration
The only way to supply muscles with energy for a long amount of time
Releases energy slowly – why athletes pace themselves
Glycogen stored in muscles provides energy for 20 minutes or so
After that other molecules are broken down
Help people loose weight
Allow animals to hibernate
At the beginning of a race muscles use all forms of energy, but stored ATP and lactic acid fermentation can only supply energy for a limited time