the metabolic function of fermentation is to:
a. oxidize NADH to NAD+ so that glycolysis can continue
b. reduce NADH to NAD+ so that more ATP can be produced by the electron transport chain
c. produce lactate during aerobic exercise
d. oxidize pyruvate in order to release more energy
The metabolic function of fermentation is to:
a. Oxidize NADH to NAD+ so that glycolysis can continue.
During fermentation, NADH molecules are converted back into NAD+ by transferring their electrons to an organic molecule like pyruvate or acetaldehyde. This regeneration of NAD+ allows glycolysis to continue producing ATP under anaerobic conditions when there is no oxygen available for cellular respiration.
The metabolic function of fermentation is option a. to oxidize NADH to NAD+ so that glycolysis can continue.
To understand why fermentation serves this purpose, let's break it down step by step:
1. Glycolysis: It is the initial step in glucose metabolism, where glucose is broken down into two molecules of pyruvate. This process generates a small amount of ATP and NADH.
2. Oxidation of NADH: During glycolysis, NAD+ (nicotinamide adenine dinucleotide) is reduced to NADH. NADH carries high-energy electrons that can be used to generate ATP, but in order for glycolysis to continue, the NADH molecule needs to be oxidized back to NAD+.
3. Electron Transport Chain (ETC): In cellular respiration, the NADH produced during glycolysis is typically taken to the electron transport chain, where it donates its electrons to generate ATP through oxidative phosphorylation. However, in the absence of oxygen or under certain conditions, such as during strenuous exercise, the ETC may not be able to function optimally.
4. Fermentation: In such situations, fermentation becomes essential. Fermentation is an anaerobic process that occurs in the cytoplasm of cells. It allows the oxidation of NADH back to NAD+ by transferring the electrons from NADH to an organic molecule derived from pyruvate, such as lactate or ethanol. This regeneration of NAD+ ensures that glycolysis can continue, producing a small amount of ATP.
In summary, the primary purpose of fermentation is to recycle NADH into NAD+ so that glycolysis can keep generating ATP, even when oxygen is limited or unavailable.