Notes

2.05
Cells use energy to grow and develop, move materials around, digest and build molecules, and respond to environmental changes. Without the ability to obtain and use energy, a cell could not survive. The immediate source of energy that drives the functions of a cell is a molecule called adenosine triphosphate, or ATP. As the chemical bonds are broken, energy is released. That released energy can be used by cells to regenerate ATP molecules. In turn, the energy stored in ATP can then be used to power most of the cell's functions. An organism's energy requirements are often related to size, activity, and environment.
ADP: when one phosphate is broken off of ATP, the remaining molecule is called adenosine diphosphate
ATP: stands for adenosine triphosphate; the main energy molecule used in metabolic processes of cells
Just like recharging a battery, forming ATP requires energy from an outside source. This energy can come from breaking down the food that the cell ingests, or from sunlight in the case of plant cells. Starch, glucose, and fat molecules provide long-term energy storage that can be released by chemical reactions in the cell. This released energy is used to reform ATP molecules, which are then used to provide energy that can be used by cells in their everyday functions.