ATP - Adenosine Triphosphate

ATP - Adenosine Triphosphate


ATP is the main energy molecule of cells, composed of adenine, ribose, and three phosphates. Produced in mitochondria, it releases energy when converted to ADP, powering essential life processes.


1. Full Form & Discovery



  • ATP Full Form: Adenosine Triphosphate

  • Discovered by: Karl Lohmann (1929)

  • Awarded Nobel Prize (ATP Cycle): Peter Mitchell (Chemiosmotic theory)


2. Definition (Very Important)


ATP is an energy-carrying molecule found in all living cells. It stores and provides energy for all cellular activities, so it is called the “Energy Currency of the Cell.”


3. Why ATP is called “Energy Currency”?


Because:



  • It stores energy in its high-energy phosphate bonds

  • It releases energy instantly when needed

  • All cells use ATP just like money is used for transactions


4. Structure of ATP (Diagram-type Explanation)


ATP consists of three parts:



  1.     Adenine - a nitrogenous base

  2. Ribose Sugar - a 5-carbon sugar

  3. Three Phosphate Groups - linked by two high-energy bonds

  4. ATP = Adenine + Ribose + 3 Phosphates


5. Formation (Synthesis of ATP)


ATP is produced mainly in mitochondria during cellular respiration:


ADP + Pi + Energy → ATP


Where:



  • ADP: Adenosine Diphosphate

  • Pi: Inorganic Phosphate


Other places ATP is produced:



  • Chloroplasts (during photosynthesis)

  • Cytoplasm (during glycolysis)


6. Breaking Down ATP (Hydrolysis)


When ATP breaks:


ATP→ADP+Pi+Energy



  • This released energy is used for essential cell activities like:

  • Muscle contraction

  • Active transport

  • Nerve impulse transmission

  • Synthesis of proteins, DNA, RNA

  • Cell division


7. Important Key Facts (Exam Must-Learn)



  • 1 ATP releases ~7.3 kcal of usable energy

  • ATP → ADP → AMP (energy gets reduced)

  • ATP cannot be stored for long; it must be continuously synthesized

  • Mitochondria are called “Powerhouse of the Cell” because they generate ATP

  • Every day your body uses ~50 kg of ATP (recycled continuously)


8. Nicknames of ATP



  • Energy Currency of the Cell (most important)

  • Energy Coin

  • Universal Energy Carrier


9. Easy to Remember : Mitochondria → Produce ATP → Broken into ADP → Releases Energy → Used for Cellular Work