question_answer

  Explain the process of breakdown of     glucose in a cell (a) in the presence of oxygen. (b) in the absence of oxygen.

Answer:

                  (a) In the Presence of Oxygen When breakdown of glucose is carried out in the presence of oxygen in a cell, it is called as aerobic respiration. Glucose is converted to three-carbon molecule called pyruvate. Pyruvate further breaks down in presence of oxygen to form carbon dioxide, water and release energy. + Water + Energy (b) In the Absence of Oxygen When breakdown of glucose is carried out in the absence of oxygen in a cell, it is called anaerobic respiration. This process is called as fermentation in microbes. Ethyl alcohol is produced by breakdown of pyruvate.