ADP-ATP system of energy exchange :
In 1929 Lohmann, Fiske and subbarow published their discovery that the energy exchanges compounds in all biological systems are two phosphorylated derivatives of adenosine monophosphate AMP. Viz. Adenosine diphosphate ADP and adenosine triphosphate ATP AMP is a d nucleotide formed by the combination ofadenine ribosome sugar and a phosphate molecule .It takes part in the composition of DNA and RNA also when a second phosphate molecule is added to AMP it become ADP and this addition of a third phosphate molecule is added to AMP., It molecule of ADP.
The terminal phosphate bonds to one in ADP two in ATP depicted by instead of are high energy bonds because these bind about 2.5 times more energy then ordinary phosphate bonds. An ordinary phosphate bond binds about 3000calories of energy, whereas each of the high energy terming phosphate bonds of ATP binds about 7300 calories of energy under standard conditions and about1200 calories under conditions normally found in the body to make a distinction the C-C and C-H bond energy of glucose and other fuel molecules released in oxidation processes, is called liberate energy where the energy stored in terminal high energy bonds of ATP is called bond energy the latter is the Biological energy.
A molecule of ADP is always coupled with catabolic reaction in which liberate energy is to be released. Hence the released energy is directly transferred ADP is stored in a high energy bond that links a new phosphate molecule to the ADP molecule by dehydration .forming a molecule of ATP. Similarly molecules of ATP are coupled with anabolic reactions so that energy is transferred directly to the reactions by breaking off the terminal phosphate bond of ATP is consequently reduced to ADP. That is how ATP serves as the common obligatory intermediate compound, or energy broker ( broker of energy currency) or bioenergy shuttle. That connects exergonic to endergonic reactions. Thus ADP =ADP is the most important energy transfer in living systems.
Power house of cell factory: The chief sites of catabolic breakdown of fuel compounds for energy production and ATP formation in the cells fuel mitochondria .The latter are therefore called power house or power plants of the cell factory .Form mitochondria the ATP molecules are transported into cytoplasm which is the chief site of their utilization.
Use of bioligical energy : Cellular processes that consume energy include.
Active transport: or materials into or out of the cells biosynthesis of new macromolecules for repair growth and multiplication.
Secretion of specialized products like hormones enzyme or excretions
Mechanical work : like contraction streaming or cyclosis movement of parts or particles within the cytoplasm.
Electric work like never impulse transmission and production of electricity or bio luminescence
When skeletal muscles are at work .these spend a large amount of energy in a short time .Thererfore a compound creating phosphate serves in these muscles as a reservoir of high energy phosphate bonds. It apidly transfers its phosphate bond to ADP to ensure a regular supply of ATP to the working muscle fibres.