AP BIOLOGY

Detailed explanation-1: -Fermentation is the process of producing ATP in the absence of oxygen, through glycolysis alone. Recall that glycolysis breaks a glucose molecule into two pyruvate molecules, producing a net gain of two ATP and two NADH molecules.

Detailed explanation-2: -In eukaryotic cells, glycolysis and fermentation reactions occur in the cytoplasm. The remaining pathways, starting with pyruvate oxidation, occur in the mitochondria. Most eukaryotic mitochondria can use only oxygen as the terminal electron acceptor for respiration.

Detailed explanation-3: -Mitochondria play a dominant role in respiration but not fermentation; however, they are essential for cell viability regardless of metabolic growth mode. Fermenting cells produce fewer mitochondria than respiring cells.

Detailed explanation-4: -An electron transport system is not involved in fermentation, and no ATP (Adenosine triphosphate) is created directly by the fermentation process. Fermenters make very little ATP-only two ATP molecules per glucose molecule-during glycolysis.