Respiration and Transportation in Organisms - Aerobic and Anaerobic Respiration

Cellular Respiration: The process of breakdown of food in the cell with the release of energy is called cellular respiration. It takes place in the cells of all organisms.

Aerobic Respiration: When the breakdown of glucose occurs with the use of oxygen ($O_2$), it is called aerobic respiration. It produces carbon dioxide ($CO_2$), water ($H_2O$), and a significant amount of energy.

Anaerobic Respiration: Breakdown of food that occurs without the use of oxygen is called anaerobic respiration. This process is common in organisms like yeast and in human muscle cells during heavy exercise.

Anaerobic Respiration in Yeast: Yeasts are single-celled organisms that respire anaerobically. In this process, glucose is converted into alcohol (ethanol, $C_2H_5OH$) and carbon dioxide ($CO_2$).

Anaerobic Respiration in Muscles: During heavy exercise, the supply of oxygen ($O_2$) to our muscle cells may be insufficient. To meet the high energy demand, muscles respire anaerobically, producing lactic acid ($C_3H_6O_3$) instead of $CO_2$.

Muscle Cramps: The accumulation of lactic acid ($C_3H_6O_3$) in the muscles causes muscle cramps. Relief is obtained by a hot water bath or massage, which improves blood circulation and increases the supply of oxygen to the cells.