First Law of Thermodynamics
The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed. For cells, this means energy must be harvested from the environment, such as sunlight for Autotrophs or chemical bonds in food for Heterotrophs. During processes like Photosynthesis and Cellular Respiration, energy is converted between forms, such as light energy to chemical energy or chemical energy to usable ATP. This law underscores the importance of energy conservation in all biological activities.