ATP

A nucleotide - monomer of nucleic acid 

Contains 

• Nitrogenous base= adenosine
• Pentose Sugar = Ribose
• Phosphate group= 3 phosphates

A coenzyme involved in cell reactions 

• Organic cofactor which helps an enzyme to work
• Major energy currency for cells - energy is released in a single step in small manageable amounts. Also a small molecule so will diffuse rapidly around the cell. 
• thrid phosphat group removed by hydrolysis releasing energy and forming ADP
• Reversible reaction as ADP + Pi = ATP

• Produced on the internal membranes of mitchondria and chloroplasts
• Synthesis takes place through the enzyme ATP synthetase 
• This occurs through chemiosmosis= the flow of protons down an electrochemical gradient through ATP syntethase. The synthesis of ATP also takes place by a condensation reaction between ADP and a phosphatte ion.
• In mitochondria this happens across the inner mebrane from the intermembranse space into the matrix
• In chloroplasts this occurs as the protons flow across the thylakoid membrane from the thylakoid space into the stroma 
• To maintain the concentration of protons in the intermembrane space proton pumps are required which are fuelled by the electrons from NADH and FADH. As they become oxidised and lose electrons.
• Protons then move into the intermembrane space and then move through ATP synthase to get to a lower concentration of protons. This transfer powers ATP synthase so that it can complete the condensation reaction between ADP and Pi to create more ATP
• 1 glucose molecule produces 38 ATP (glycolysis=2, krebs cycle= 2  Electron transfer chain= 34)