Cells have to carry out tens of thousands of chemical reactions to maintain
their proper function. All of these reactions need energy, but where does the
energy come from? Since the beginning of evolution, cells have developed highly
efficient metabolic systems. The specific mechanisms vary in different cell
types. For example, plant cells derive their energy from photosynthesis and animal cells rely on aerobic
respiration to fulfill their energy needs. Although the mechanisms differ, the
end goal of all metabolic systems is the same, to produce ATP molecules. Choose
from the sections below to learn about ATP and see how cells get their energy
Cellular Currency: ATP
ATP is the de facto standard of energy in cells.
Find out what makes it so special.
Plants use photosynthesis to convert sun light, CO2,
and water into sugar. In the process, ATP is also
produced. Click here to find out more.
Animal cells produce energy through an oxygen-
dependent cellular respiration. Find out more about