Question

Explain The Oxidation Of Glucose

Answer 1

Answer:

living organism requires energy simply to survive as an organized structure, let alone to perform any useful functions. In this section we explore the chemistry of the major source of the energy used by animals, the oxidation of glucose.

Biochemical, or living, systems require sources of energy. The fundamental source of energy for them is light, whose source is the sun. A small fraction (for sugar cane, 8% of incident light; for corn, 1 - 2%) of this light can be used by plants, through photosynthesis, to obtain compounds from carbon dioxide and water. The sugar glucose, whose molecular formula is C6H12O6, is formed by the overall reaction

6CO2 + 6H2O⇒ C6H12O6 + 6O2(g).

Under standard conditions of 25° C and one atmosphere pressure, the standard free energy change DG° of this reaction is +2870 kJ/mole. To make this non-spontaneous process go, 2870 kJ/mole must be supplied by energy from elsewhere, in this case light. The synthesis of glucose may be taken as typical of the production of carbohydrates, or even of organic compounds generally, in plants.

Animals, such as human beings, are not capable of photosynthesis and so they derive their energy by running reactions such as this backwards, degrading the glucose to, ultimately, carbon dioxide and water. The overall reaction of glucose oxidation is the reverse of the overall reaction for its formation. Fot he reverse reaction the standard free energy change DG° must then be -2870 kJ/mole.

The basic problem in animal metabolism is that 2870 kJ is too much energy to use in one lump; it has to be broken down into smaller units. This can be seen if we consider the relationship DGo = -RT ln K; DG° = -1.363 log K, at 25°C.