Role of ATP Molecules

ATP Molecules

For each glucose molecule that is decomposed. 38 molecules of ATP can be produced. Two of these are the result of anaerobic respiration, while the rest are formed during the aerobic phase. Each ATP molecule consists of three main parts—an adenine ponion, a ribose portion, and 3 phosphates in a chain. 

(Note the similarity between the structure of an ATP molecule and that of a nucleotide from a nucleic acid molecule).

As energy is released during cellular respiration, some of it is captured in the bond of the end phosphate of an ATP molecule. This energy is quickly transferred to some other molecule involved in a metabolic process When this happens, the terminal, high energy phosphate bond of the ATP is broken, and the energy of this bond is released Such energy is needed whenever cellular work is performed, as when muscle cells contract, membranes carry on active transport, or cells synthesize substances.

An ATP molecule that has lost its terminal phosphate becomes an ADP (adenosine diphosphate) molecule However, the ADP molecule can be converted back into an ATP by capturing some energy and a phosphate Thus,  ATP and ADP molecules shuttle back and forth bereave the energy-releasing reactions of cellular respiration and the energy - initializing reactions of the cell. 

Although ATP is not the only kind of energy carrying molecule within a cell, it is the primary one and without a source of ATP most cells die quickly.