3. ● Fermentation: the release of energy
from food molecules in the absence of
oxygen (anaerobic)
● Enables cells to carry out energy production in
the absence of oxygen
● result of glycolysis + fermentation yields 2
ATPmolecules per 1 molecule of glucose .
7. 1) Alcoholic Fermentation:
● occurs in yeast cells & some
other microorganisms
● pyruvic acid is broken down
into a 2-Carbon alcohol
plus carbon dioxide
2 Fermentation Pathways:
8. Alcoholic Fermentation:
●Important to brewers & bakers!
– When yeast in dough runs out of oxygen it
ferments, giving off bubbles of carbon dioxide
gas— which forms air space in bread
– Alcohol produced in the dough evaporates
when bread is baked
• *(when the level of alcohol reaches 12%,
yeast cells die)
9. 2) Lactic Acid Fermentation:
● pyruvic acid from glycolysis is
converted to lactic acid
● lactic acid is produced in
muscles during rapid exercise
(body can't supply enough O2
to the tissues)
● the build-up of lactic acid
causes a burning, painful
sensation in your muscles
10.
11.
12. What happens if your cells
aren’t getting enough
oxygen?
● Krebs Cycle & E.T.C. CANNOT proceed without
oxygen
● Instead, FERMENTATION occurs
– PyruvicAcid builds up in animal muscle cells & is
converted to LACTIC ACID… feel the burn!
– In other organisms, the pyruvic acid builds up,
ferments, and becomes alcohol
13.
14.
15.
16. Energy & Exercise: Quick
Energy
● Muscle cells only contain enough ATP for a
few seconds of energy, or a “burst” energy
– e.g. – an emergency, starting gun of race
● When this is gone, cells resort to lactic acid
fermentation which can provide enough ATP
for about 90 seconds
17. Energy & Exercise: Long Term Energy
● If a race or energy need is longer, your body
must go through cellular respiration to
get enoughATPto continue
Even well-conditioned athletes have to pace themselves
Your body stores energy in muscle cells and liver in the form
of GLYCOGEN
these stores are enough to last for 15-20 minutes of
activity when broken down through cellular respiration
After this, your body begins to break down other molecules,
including fats, for energy
– This is why aerobic exercise is beneficial for weight control!!
