Glycolysis is the pathway of respiration (converting glucose into pyruvate) that is conducted in the absence of oxygen. and fermentation is the final step of the glycolysis. This process yields two net ATPs (adenosine triphosphate); these are considered the energy currency of the cell. Fermentation in plant cells yields ethyl alcohol and carbon dioxide from pyruvic acid. In animal and bacterial cells, pyruvic acid ferments to lactic acid. Carbon dioxide is not produced as a primary or secondary product.
Glycolysis
The pathway of glycolysis happens in all types of cells. In all cells, the pathway is the same until the last step of fermentation occurs.
Animal Cells
Fermentation in animal cells results in pyruvic acid being converted to lactic acid in the body. This is evidenced in tired muscles and the pain that comes with it. Lactic acid buildup is responsible for it.
Bacterial Cells
In bacteria, fermentation converts pyruvic acid to an intermediate called acetalaldehyde. It's eventually converted to lactic acid.
Industry Use
Cheese is produced by fermentation. Specifically, the sugar from milk is fermented to lactic acid. Then, the enzyme rennet is added. Yogurt is a product of bacterial fermentation, and lactic acid gives yogurt its distinct taste.
Considerations
Carbon dioxide is a product of aerobic respiration in the presence of oxygen. The pathway of the citric acid cycle eventually produces the bulk of ATPs used by the body.
Tags: lactic acid, pyruvic acid, Carbon dioxide, converted lactic, converted lactic acid, Glycolysis pathway