A student drew the following model.

Glycolysis

Krebs cycle

Electron transport chain

ATP

What is the energy input in the process shown?

I believe the options are:

A. chemical energy in the bonds of food molecules

B. carbon energy in molecules of carbon dioxide

C. solar energy in the rays of sunlight

D. electrical energy in the form of hydrogen ions

The correct answer is A. Chemical energy in the bonds of food molecules

Explanation:

Glycolysis, Krebs Cycle and electron transport chain are the major steps in cellular respiration. Cellular respiration is the break down of sugars, particularly glucose into energy yielding molecules such as ATP, NADH and FADH2.

C6H12O6 + 6O2 - -> 6CO2 + 6H2O + ATP