Lactic Acid Fermentation

1. Lactic Acid Fermentation By Jessica Moses (3A) Jessie O’Kelley (4A) Jesus Miranda (6B)

2. Third Strike Lactic Acid Fermentation • He wound his arm around, ready to throw the last pitch of the game. • He holds his breath…biceps release, triceps contract. • He can feel the strain, the fibers tightening and the cells metabolizing carbohydrates. • Sweat trickles down his face. • Metabolism shifts into the anaerobic domain. • Muscle energy is produced along with that painful by-product: Lactic Acid. • He grinds his teeth, ignoring every signal his body is giving him to stop. • The finite amount of carbohydrate (glycogen) stored in his muscles and liver is totally exhausted.

3. He closes his eyes and listens. • He can hear the booming voice of the telecaster overhead. • His arm is frozen in mid-pitch. • Licking his lips he lets his mind trail off to when he was a boy. • He’s sitting on the bench, crunching on a pickle before pitching his first little league game. • He made the same face he is making now; he cringes. • He can feel the sourness coating his tongue; see the vat of giant pickles. • Each preserved by salt leaching out the sugars of the raw cucumbers then lactic-acid-bacteria taking over. • He shakes the memory.

4. “Hey man, get your head in the game, let’s go!” • He feels the catcher throw dirt at his cleats. • He twists his wrist and grips the ball, squinting into the sun; he winds his arm up again. • He can feel the pores on his skin soaking up the vitamin D, closing his eyes he sees his high school Biology teacher. • Lactic Acid Fermentation • The board is covered in formulas…She’s pointing to her arm, flexing it a little, then pointing to one formula in particular: • 2Pyr. 2Lactic Acids • 2NAD 2NADH • He tightens his grip on the ball…biceps release, triceps contract. His muscles hug his bones, begging for him to stop. • He imagines the process going on in his body…the jumbled letters written on the board: • NADH is oxidized to NAD˖ as pyruvate is reduced to lactate. • He opens his eyes…blinks…swings his arm…releases the ball. L.A.F

5. Strike one… Strike two… Strike three…

6. Summary of the Processes of Lactic Acid Fermentation • All types of fermentation provide an anaerobic step that recycles NADH back to NAD˖. During a process called Lactic Acid Fermentation, however, NADH is oxidized to NAD˖ as pyruvate is reduced to the ionized form of lactic acid, lactate. Lactic acid fermentation is done by some fungi, some bacteria like the Lactobacillusacidophilusin yogurt, and sometimes by our muscles. On normal circumstances, our muscles would do cellular respiration just like the rest of our body, using the oxygen supplied by our lungs and blood, but when pushed to the limit, our muscles will turn over to lactic acid fermentation in an effort to recycle some of the energy being used.

7. During Lactic Acid Fermentation, 2-pyruvate molecules are turned into 2 lactic acids and then 2 NADH’s produce 2 NAD+. This Fermentation process is basically the “back-up plan” to cellular respiration. As in muscle cells, the second resort after having used up all available O2 supplemented by the blood and lungs, is to switch over to Lactic Acid Fermentation, which will provide the muscles with what they need to function.

8. Side note: There are people that have rare genetic diseases where their body lacks one enzyme to do cellular respiration and they rely more heavily on Lactic Acid Fermentation. As is the case with people that have Anemia. This means that the person isn’t generating enough red blood cells to carry enough oxygen to the cells to harvest enough energy needed to do cellular respiration, thus, their body turns to Lactic Acid Fermentation. Also, in the case of some cancer victims, their chemotherapy has limited the generating of red blood cells and can also cause the body to rely more heavily on Lactic Acid Fermentation.