Cellular Respiration

Autotrophs and Heterotrophs

Living organisms require a continuous input of energy to maintain cellular and organismal functions such as growth, repair, movement, defense, and reproduction. Cells can only use chemical energy to fuel their functions, therefore they need to harvest energy from chemical bonds of biomolecules, such as sugar...

Everything that is alive requires an energy source to fuel its activities. Ultimately, that source of energy is the sun. How then did the organisms on Earth harness this energy? It all starts with the photosynthesizers. These organisms are able to take carbon dioxide and water and then use energy captured from the sun as photons to force these m...