Question

How many ATP molecule could maximally be generated from one molecule of glucose if the complete oxidation of one mole of glucose to $$C{O}_2$$ and $$H_{2}O$$ yields 686 Kcal and the useful chemical energy available in the high energy phosphate bonds of one mole of ATP is 12 Kcal?
(A) Fifty-Seven
(B) One
(C) Two
(D) Thirty

Answer 1

Hint: When food is oxidized, breakdown of glucose to carbon dioxide necessitates the presence of oxygen. The breakdown of glucose leads to the release of energy and hence, ATP molecules are produced.

Complete answer:
If one mole of glucose yields total energy of 686 Kcal after complete oxidation and it is given that the available chemical energy in phosphate bonds of one mole of ATP is 12 Kcal. Then the number of molecules that could be generated from one glucose molecule could be calculated by dividing the total energy by energy of one mole of ATP i.e. 686÷12. This gives an answer of 57 ATP.

Therefore the correct option is (A) Fifty – Seven

Additional Information: Glucose is the favoured substrate for Respiration. All carbohydrates are usually converted into glucose and then are oxidised to release Energy. There are two types of Respiration – (a) Aerobic Respiration (B) Anaerobic respiration. The complete oxidation of food happens in Aerobic respiration which involves a series of steps. The first step is Glycolysis which occurs in cytosol. The net ATP consumed in glycolysis is 2 ATP. Glycolysis is followed by Formation of Acetyl COA. The third step is Krebs cycle and the last step is ETS. Anaerobic respiration takes place in bacteria, plants, RBC, muscle tissue etc. This is an incomplete oxidation where food is oxidized into alcohol or organic acids without use of oxygen.

Note: The net gain of ATP molecules during Aerobic respiration of one molecule of glucose is 36 ATP which is the total gain of ATP from all EMP pathways, Link reaction or Gateway reaction and Krebs Cycle.