1. Objec&ve 2.15: ATP
• Describe the generalized reversible reac&on
for release of energy from ATP and explain the
role of ATP in the cell.

2. Adenosine Triphosphate (ATP)
• Temporary molecular storage of energy as it is being
transferred from exergonic catabolic reac&ons to
cellular ac&vi&es
– muscle contrac&on, transport of substances across cell
membranes, movement of structures within cells and
movement of organelles
• Consists of 3 phosphate
groups aJached to
adenine & 5‐carbon
sugar (ribose)

3. Forma&on & Usage of ATP
• Hydrolysis of ATP (removal of terminal
phosphate group by enzyme ‐‐ ATPase)
– releases energy
– leaves ADP (adenosine diphosphate)
• Synthesis of ATP
– enzyme ATP synthase catalyzes the addi&on of
the terminal phosphate group to ADP
– Generated during the catabolism of glucose

4. ATP/ADP Cycle
ATP
Reactions Reactions
release energy require energy
↓ ↓
Form ATP Use ATP
ADP + Pi