Comparisons of Anaerobic & Aerobic Cellular Respiration

Cellular respiration is the process in which cells obtain energy from food. This can be done aerobically, with oxygen, or anaerobically, without oxygen. Anaerobic respiration is also called fermentation. Both types of cellular respiration begin with a molecule of glucose. The energy produced and utilized by the cell is called adenosine triphosphate (ATP).

Glycolysis

• The first step in both aerobic and anaerobic cellular respiration is glycolosis. Its process takes the molecule of glucose, which has six carbons, and breaks it down into two molecules of pyruvic acid, which has three carbons. This process takes place in the cytoplasm of the cell and does not require oxygen. Two ATP molecules are used in this process and four are made.

Kreb's Cycle

• In eukaryotic cells, aerobic respiration continues in the mitochondria. According to the Clinton Community College's Biology Web page, the pyruvic acid enters the mitochondria and is converted into acetyl CoA by coenzyme A. After the completion of the Kreb's cycle, electrons are removed from the pyruvic acid and carried in the molecules NADH and FADHv2. Carbon dioxide is a byproduct of this process.

Electron Transport Chain

• The next step in aerobic respiration is the electron transport chain. The FADHv2 and NADH transfer the electrons they gained in the Kreb's cycle into the electron transport chain. Oxygen is the final acceptor for these electrons, making this process aerobic. After the chemical reactions that occur in this chain, water molecules are released as a byproduct. This process produces energy and, along with the help of ATP synthase, 34 ATP molecules are produced and the aerobic respiration is complete.

Fermentation

• When oxygen is not available for aerobic respiration, anaerobic respiration continues in the form of fermentation. According to the Biology Web, after glycolysis, the pyruvic acid is transformed into an alcohol in plants or lactate in animals with the use of NADH. Only two net ATP molecules are produced from fermentation in the glycolysis phase of respiration.

When Anaerobic Cellular Respiration Is Used

• Aerobic respiration is far more efficient than anaerobic respiration. In the case of exercise, anaerobic respiration is what causes muscle soreness by the buildup of lactate in the muscles. According to the Biology Web, the lactate is converted back to pyruvic acid during recovery. Yeast is another example of an organism that uses anaerobic respiration. The alcohol produced by yeast is found in beer and liquor.