Anabolic Processes

A plant cell that contains chlorophyll is an Autotroph. It makes sugar from carbon dioxide and water by photosynthesis:

6CO2 + 6HO -----> C6 H12 O6 + 6O2 

from this sugar, together with absorbed mineral salts, the cells builds up complex carbohydrates, fats and oils , proteins, nucleic acids, vitamins and various other macromolecules. These are the anabolic process by which a plant cell utilizes the sun energy and the matter in its environment for making its own living material, the protoplasm. The production of new protoplasm all the time is necessary for cell repair, growth and reproduction, and as a source of energy. From its energy store,  the plant cell releases the energy it needs by cellular respiration.

     Not all cells of Autotrophs use the Sun's energy for making protoplasm. Some bacteria cell use inorganic materials as a source of energy. They break down inorganic compounds such as hydrogen sulphide, ammonia or iron salts and use the energy released for their anabolic processes.

   The anabolic activities of plant cells result in the production of inorganic macromolecules. These molecules are not only used by plant cells, but also by cells of heterotrophs such as animal cells. This happens when a consumer (heterotroph) feeds on a producer (Autotroph). The macromolecular food is broken down by the cells of the heterotroph into simple organic molecules.

    These some organic molecules are rich sources of chemical energy. The animal cell uses such molecules to build up animal type proteins. Fats and oils, and carbohydrates. The macromolecules formed by these anabolic reactions are used for the production of new protoplasm. Energy for the reactions comes from ATP molecules that are formed during cellular respiration.

   The cells of Autotroph and heterotrophs derive energy and matter from their environment and use them to build up complex organic macromolecules. However, cells of Autotroph can carry out anabolic reactions, like photosynthesis, which use energy from outside sources directly and produce energy rich organic compounds. This is something that cells of heterotrophs cannot do. They have to take in ready made, energy rich organic compounds which only Autotrophic cells can make. Thus. Heterotrophic cells depends on photosynthesis product of autotrophic cells.