-Photosynthesis occurs in the chloroplast, an organelle specific to plant cells. The light reactions of photosynthesis occur in the thylakoid membranes of the chloroplast.
-Energy Cycle in Living Things The chloroplasts collect energy from the sun and use carbon dioxide and water in the process called photosynthesis to produce sugars. Animals can make use of the sugars provided by the plants in their own cellular energy factories, the mitochondria.
-Cyanobacteria, often known as blue-green algae, are among the most abundant organisms in oceans and fresh water. They are similar to green plants because they can use the energy from sunlight to make their own food through photosynthesis.
-What is a microbe? A microbe is any living organism that spends its life at a size too tiny to be seen with the naked eye. Microbes include bacteria and archaebacteria, protists, some fungi and even some very tiny animals that are too small to be seen without the aid of a microscope.
-Plants, algae and cyanobacteria use a chemical reaction known as photosynthesis to create the materials they need from what's around them. Plucking carbon dioxide from the air, water from the ground and light from the sun, land plants make sugar and kick out oxygen as a waste product.
During the early days of the Earths life there was no oxygen but there was plenty of CO2 which the autotrophs took and used as food while discarding the excess which was the oxygen.
