ADP vs. ATP

Main Difference

The main difference between ADP and ATP is that ADP molecule consists of two molecules of the phosphate group from ATP, and the third molecule is a breakdown which results in the release of the high amount of energy, whereas ATP consists of three molecules of phosphate and the third phosphate is bonded to other phosphate groups having a high energy bond.

Difference Between ADP and ATP

Comparison Chart

ADP vs. ATP

The abbreviation of ADP is Adenosine Di Phosphate, while the abbreviation of ATP is Adenosine Triphosphate. The molecular structure of ADP contains adenosine (an adenine ring and a ribose sugar) and two phosphate groups (diphosphate), whereas the molecular structure of ATP contains adenosine (an adenine ring and a ribose sugar) and three phosphate groups (triphosphate). ADP consists of two phosphate groups; on the other hand, ATP consists of three phosphate groups.

The chemical formula of ADP is C₁₀H₁₅N₅O_10­P₂; on the contrary, the chemical formula of ATP is written as C₁₀H₁₆N₅O₁₃P₃. The molar mass of ADP consists of 427.201 g/mole; conversely, the molar mass of ATP consists of 507.18 g/mol. The density of ADP is calculated as 2.49 g/mL; on the flip side, the density of ATP is calculated as 1.04 g/cm³.

ADP is generally a low energy molecule as matched to ATP; on the flip side, ATP is usually a high-energy molecule as related to ADP. The energy releasing mechanism for ADP is ADP + H2O → AMP + PPi; on the contrary, the energy-releasing mechanism for ATP is ATP + H2O → ADP + Pi ΔG˚ = −30.5 kJ/mol (−7.3 kcal/mol).

Functions of ADP are described as it is used in blood platelet activation, or it plays a role in mitochondrial ATP synthase complex, used in catabolic pathways such as glycolysis, citric acid cycle, and oxidative phosphorylation. On the flip side, functions of ATP are described as it plays a role in the synthesis of macromolecules such as DNA, RNA, metabolism in cells, amino acid activation, and protein, active transport of molecules, maintaining cell structure, and contribute to cell signaling. The less amount of energy is stored in the ADP molecule as it contains only two molecules of phosphate, while a large amount of energy is stored in ATP as it consists of three molecules of phosphate.

The third molecule of phosphate is added to the ADP by using some energy from food during the conversion of ADP to ATP, whereas the third molecule of phosphate is hydrolyzed by water or releasing energy during the conversion of ATP to ADP. The ADP molecule is generally formed from ATP by the process of mitosis and conserving homeostasis; on the contrary, the ATP is formed from ADP by fermentation, photophosphorylation, and cellular respiration.

What is ADP?

Adenosine Diphosphate (ADP) generally states to the organic compound, which works as the final product of the energy transmission of the ATP. ADP is considered an important component of nucleic acids as it is one of the most significant and one of the most abundant molecules present in the cell.

The molecular structure of ADP from which it is formed contains adenosine (an adenine ring and a ribose sugar) and two phosphate groups (diphosphate). This structure of ADP is vital for energy flow in biological systems.

ADP is formed as a product of de-phosphorylation of a molecule of ATP through enzymes called ATPase. The IUPAC name given to ADP is [(2R,3S,4R,5R)-5-(6-aminopterin-9-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphonic hydrogen phosphate. The ADP molecules are also called as adenosine 5′-diphosphate.

Functions of ADP

• It is used in blood platelet activation
• It plays a role in mitochondrial ATP synthase complex
• Used in catabolic pathways such as glycolysis, citric acid cycle, and oxidative phosphorylation
• It usually stores and releases energy
• It gives the energy required to receive and send ions that transmit signals between neurons.

What is ATP?

Adenosine Triphosphate (ATP) usually mentions to an organic molecule which consists of adenosine and three phosphate molecules and assists as the energy bank of the cell. ATP is specifically used by biological individuals as a coenzyme of intracellular chemical energy transmission within cells for a breakdown as it is the central energy transporter molecule used in living organisms.

ATP is formed from ADP by fermentation, photophosphorylation, and cellular respiration. The molecular structure of ATP from which it is composed usually contains adenosine (an adenine ring and a ribose sugar) and the three phosphate groups (triphosphate).

Biosynthesis of ATP By

• Glycolysis: 2NAD+ + 2 Pi + 2 ADP + Glucose = 2 pyruvates + 2 ATP +2 H₂O + 2 NADH
• Fermentation: Glucose = 2CH₃CH(OH)COOH + 2 ATP

Functions

• It plays a role in the breakdown in cells
• Amino acid activation
• Synthesis of macromolecules such as DNA, RNA, and protein
• Active transport of molecules
• Maintaining cell structure
• Contribute to cell signaling

Conclusion

Above discussion concludes that the ADP molecule consists of two molecules of a phosphate group, and the third molecule is a breakdown which results in the release of a high amount of energy, but it is generally a low energy molecule, whereas ATP consists of three molecules of phosphate and the third phosphate are bonded to other phosphate groups with having a high energy bond, and it is a high energy molecule.