Adenosine Triphosphate (ATP) • “universal energy molecule” • It’s why we eat. • Structure • Adenine, a N base • Ribose, a 5 C sugar • Chain of 3 phosphates
How does ATP work? • A phosphate is transferred to another molecule • iP transfer is enzyme controlled • Phosphorylated molecule becomes more reactive
How does ATP work? • Make substrates more reactive. • Make uphill, building reactions a bit more feasible • Exergonic hydrolysis of iP is coupled to endergonic process.
Regeneration of ATP • Amount of ATP in any cell at any moment is surprisingly small • Average bacteria cell, < 5 million, only enough to sustain activity for a second or two. • Human body has enough ATP “on hand” to last about 20 seconds. • ATP supplies must be continually replenished (that’s why we eat, and breathe)!
Cellular Respiration • Process by which cells extract energy from food • Literally it’s about using bond energy (electrons) to regenerate ATP • May be anaerobic or aerobic