AP BIOLOGY

Detailed explanation-1: -In the process of fermentation the NADH + H+ from glycolysis will be recycled back to NAD+ so that glycolysis can continue. In the process of glycolysis, NAD+ is reduced to form NADH + H+. If NAD+ is not present, glycolysis will not be able to continue.

Detailed explanation-2: -The process of fermentation results in the reduction of pyruvate to form lactic acid and the oxidation of NADH to form NAD+. Electrons from NADH and a proton are used to reduce pyruvate into lactate.

Detailed explanation-3: -NAD+ can be regenerated in the cytoplasm from NADH through the conversion of pyruvate to lactate by the lactate dehydrogenase (LDH), thereby maintaining active aerobic glycolysis [5].

Detailed explanation-4: -Under aerobic conditions, NAD is regenerated when the electrons from NADH molecules are shuttled into the mitochondria and the electron transport chain. The electrons from NADH eventually make their way to molecular oxygen, which is reduced to water.

Detailed explanation-5: -Answer and Explanation: The process that uses oxygen to regenerate NAD+ and FADH for use in respiration is called the electron transport chain. NADH and FADH2 generated during glycolysis and the Krebs cycle are oxidized back to NAD+ and FADH. The electrons are transferred to the electron transport chain.