Question

What are the end products of Anaerobic respiration?

Answer 1

Hint: Anaerobic respiration is a type of respiration through which cells can break down glucose to generate energy in the absence of oxygen. This is in contrast to aerobic respiration, which needs oxygen to produce energy. The two important types of anaerobic respiration are Lactic acid fermentation and alcoholic fermentation. Anaerobic respiration occurs in lower organisms such as bacteria and yeast. Lactic acid fermentation occurs in humans during heavy activities.

Complete answer:
In anaerobic respiration electron acceptors other than molecular oxygen are used. This process takes place with the help of a respiratory electron transport chain.
In aerobic respiration, electrons travel in an electron transport chain and the final electron acceptor will be oxygen. Molecular oxygen is a strong oxidizing agent therefore is an excellent electron acceptor. Whereas in anaerobes, other less oxidizing substances such as nitrate, fumarate, sulfate are used. These electron acceptors have smaller reduction potentials than oxygen.
The end products of anaerobic respiration also differ from that of aerobic. Carbon dioxide along with lactic acid or ethanol are produced as end products. Lactic acid is produced during lactic acid fermentation and ethanol is produced during alcoholic fermentation. The reaction of the process is given below.
Lactic acid fermentation:
\[{C_6}{H_{12}}{O_6}\;\left( {glucose} \right) + {\text{ }}2ADP{\text{ }} + {\text{ }}2pi{\text{ }} \to {\text{ }}2lactic{\text{ }}acid{\text{ }} + {\text{ }}2ATP\]
Alcoholic fermentation:
\[{C_6}{H_{12}}{O_6}\;\left( {glucose} \right){\text{ }} + {\text{ }}2{\text{ }}ADP{\text{ }} + {\text{ }}2{\text{ }}pi{\text{ }} \to {\text{ }}2{\text{ }}{C_2}{H_5}OH{\text{ }}\left( {ethanol} \right){\text{ }} + {\text{ }}2{\text{ }}C{O_2}\; + {\text{ }}2{\text{ }}ATP\]
Lactic acid fermentation usually takes place in muscle cells during intense exercise due to depletion of oxygen. Alcoholic fermentation is done by yeasts during cellular respiration. Yeast fermentation is useful for wine and beer making.

Note:
Anaerobic respiration usually takes place in the cytoplasm of an organism. This is because most cells that carry out anaerobic respiration do not have membrane bound organelles. The steps of reactions are also typically shorter than in aerobic respiration. Anaerobic respiration is of greater ecological importance as they help in balancing nitrogen, sulfur, and carbon cycles in the environment.