AP BIOLOGY

Detailed explanation-1: -Glycolysis, which is the first step in all types of cellular respiration is anaerobic and does not require oxygen. If oxygen is present, the pathway will continue on to the Krebs cycle and oxidative phosphorylation. However, if oxygen is not present, some organisms can undergo fermentation to continually produce ATP.

Detailed explanation-2: -When oxygen is not present, pyruvate will undergo a process called fermentation. 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+.

Detailed explanation-3: -Fermentation is another anaerobic (non-oxygen-requiring) pathway for breaking down glucose, one that’s performed by many types of organisms and cells. In fermentation, the only energy extraction pathway is glycolysis, with one or two extra reactions tacked on at the end.

Detailed explanation-4: -Aerobic fermentation occurs in the presence of oxygen. It usually occurs at the beginning of the fermentation process. Aerobic fermentation is usually a shorter and more intense process than anaerobic fermentation.

Detailed explanation-5: -Respiration in the absence of oxygen is called anaerobic respiration. It is also termed fermentation. In this process, glucose is partially broken down anaerobically which produces two ATP.