C1.2 Cell respiration
ATP, the cell energy currency
Adenine + Ribose = Adenosine
Adenosine + 3 Phosphates = Adenosine Triphosphate = ATP
ATP is a nucleotide (the AMP part can be used in making RNA strands during transcription making DNA strands during DNA replication)
Universal energy currency
– Used as the source of energy for all chemical reactions, active transport, endo/exocytosis…
Stores energy in the bonds between its phosphate groups
The bond between the second and third phosphates is broken to give its energy
ATP→ ADP + Pi
ADP = Adenosine diphosphate
Pi = Inorganic phosphate
A phosphate which is not inside an organic molecule
Energy used by cells
Formation of ATP during cell respiration
”ATP is a small, water-soluble molecule”
– Moves easily inside organisms by facilitated diffusion
”ATP is a small, water-soluble molecule”
– Transfer small amount of energy at a time
– Sufficient for individual reactions
Glucose contains much more energy
Cell respiration produces 38 ATP per molecule of glucose
– Glucose transports much more energy than individual reactions require
– ATP was “chosen” as the universal energy currency
How the cells use energy
