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 makes ATP without oxygen, which involves glycolysis only. Fermentation recycles NAD+, and produces 2 ATPs. In lactic acid fermentation, pyruvate from glycolysis changes to lactic acid. This type of fermentation is carried out by the bacteria in yogurt, and by your own muscle cells.

Detailed explanation-4: -Some cells obtain their energy through fermentation, an energy-releasing process that does not require oxygen. Fermentation provides energy for cells without using oxygen. One type of fermentation occurs in yeast and some other single-celled organisms.

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.