The original source of energy for the activities of living things is the sun . The greater the activity and energy use of a cell, the greater the number of mitochondria it contains. Cells take in nutrients and give off wastes. When equilibrium is reached in a cell materials enter and leave the cell at the same rate. Cells need energy to carry out activities.
Green plants convert light energy from the sun into sugars through the process of photosynthesis.
When we eat and digest green plants, glucose enters the cells of our bodies by the process of diffusion. Mitochondria use the glucose along with oxygen, through a chemical reaction in the process of respiration, to release the energy cells need to carry out their activities. Name two functions of the cell membrane. A bottle of ammonia is left open in the back of a classroom. A plant cell is surrounded by a particular substance.