Metabolism and Energy Transformation in Body Cells - Renata Armenakovna Petrosova 2004

Energy Metabolism
Efficiency of Energy Metabolism

The total amount of energy released during METABOLISM/26.html">Energy Metabolism is 2880 kJ/mol. Part of this energy is dissipated as heat, while another part is stored in 38 ATP molecules. The energy stored in 1 mol of ATP is 30.6 kJ/mol. Thus, 38 ATP molecules store 38 × 30.6 = 1162.8 kJ/mol. The efficiency of the Respiration process is:

(1162.8: 2880) · 100 % = 40.37 %.

Thus, AEROBIC GLUCOSE OXIDATION stores 40.37 % of the energy in the form of ATP.

Anaerobic oxidation yields only two ATP molecules. Let us calculate the efficiency of this process. The total amount of energy released during Alcoholic Fermentation is 210 kJ/mol. The efficiency of alcoholic fermentation is:

(2 — 30.6: 210) · 100 % = 29.14 %.

The total amount of energy released during Lactic acid fermentation (Glycolysis in Muscles) is 150 kJ/mol. The efficiency of lactic acid fermentation is:

(2 — 30.6: 150) · 100 % = 40.8 %.

Let us compare these data with the efficiency of various engines. The energy efficiency of the best turbines is 20–25%. For internal combustion engines, it is 35%. The efficiency of organic matter oxidation in living organisms is beyond doubt.

Respiration, or Biological Oxidation, and combustion processes share similar end results, but differ in energy conservation. During combustion, all energy is converted into light and heat, with none of it being stored. In The process of respiration, a portion of the energy is conserved in ATP molecules, which are subsequently utilized in anabolic reactions during the synthesis of Organic compounds.