ATP: The Energy Molecule

What is ATP? ATP stands for “adenosine triphosphate”. This molecule is known as the “energy currency” for organisms.

Why is ATP important? ATP is a small molecule that delivers energy whenever energy is needed in a cell.

What does ATP look like? ATP is a molecule that contains adenine, ribose and 3 “phosphate bonds” that store energy. The 3 rd phosphate bond contains the most energy. Adenine Ribose P P P

ATP

Energy from ATP When ATP loses its 3 rd phosphate bond, it gives off energy and turns into ADP. ADP stands for “adenosine diphosphate”.

ATP and ADP

The ATP – ADP Cycle ATP ADP + P + energy

ATP and ADP

ATP as the Energy Currency ATP delivers small amounts of energy. If an organism requires more energy, it needs to use up more ATP. ATP is the same energy molecule in every organism.

So, where does ATP come from? ATP is made in the mitochondria of the cell in a process called cell respiration. Cell respiration – the process by which a cell converts glucose and oxygen into carbon dioxide, water and ATP. Cell respiration occurs in the mitochondria. ATP Video

Photosynthesis Photosynthesis is the process by which autotrophs (in plants and some protists) use the sun's energy, carbon dioxide and water to make chemical energy (food - in the form of glucose) and oxygen gas.

Chemical Equation for Photosynthesis 6CO H 2 O + light C 6 H 12 O 6 + 6O 2

Chemical Equation for Cell Respiration C 6 H 12 O CO 2 6CO 2 + 6H 2 O + ATP

Compare the Equations! Photosynthesis: 6CO H 2 O + light C 6 H 12 O 6 + 6O 2 Cell Respiration: C 6 H 12 O CO 2 6CO 2 + 6H 2 O + ATP