Cellular respiration is the ability of a cell in an organism to metabolize chemicals in the production of adenosine triphosphate (ATP), the main energy molecule of the cell. There are two forms of cellular respiration. Chemotrophic respiration, which is used by animals and phototrophic respiration (a.k.a. photosynthesis) used by plants and fungi. Chemotrophic respiration requires oxygen to efficiently make ATP and gives off carbon dioxide as a waste product. Photosynthesis requires carbon dioxide and gives off oxygen as a waste product. Further analysis of these two types of respiration will show why these processes are related and how they differ.
Photosynthesis is the process in which plants/fungi process light photons and carbon dioxide into energy in the form of ATP and NADPH. This energy is then plugged into Calvin cycle and the biosynthesis of starch and sucrose. Photosynthesis is mainly synthesized in the chloroplast of the cell. The Chloroplast is made of three membranes which help to organize and regulate photosynthesis by creating specialized regions for the metabolic pathway to produce products and reactants. The inner membrane contains the stroma. The stroma contains thylakoids and the enzymes specific to the glycolate pathway. The thylakoid is made up of stack of grana and these grana are interconnected. These stacks of thylakoid layer together forming lumen which is semipermeable to light photons and is the proton gradient that allows for the synthesis of ATP.
The absorption of light in the form of photons through the thylakoid membrane into the lumen is the first step of photosynthesis. This photons absorbed through the lumen go through photochemical reduction in which they are absorbed into pigments such as chlorophyll. Chlorophyll molecules are placed into units bound within thylakoid membrane. These groups are a combination of necessary pigments and proteins which make up the membrane complexes of the Electron Transport Chain (ETC). The ETC is responsible for pumping the protons through the gradient and to the ATP Synthase complex producing ATP and NADPH and completing the second step of photosynthesis. ATP and NADPH are released into the stroma of the chloroplast are fed into the Calvin Cycle along with carbon dioxide.
The Calvin Cycle is responsible for converting carbon dioxide into sugar and releases oxygen as a product. This cycle is dependent on carbon dioxide molecules which enter the cell via specialized porins called somata; from here carbon dioxide diffuses throughout the plant cell with ease. Three molecules of carbon dioxide and 3 molecules of water enter the cycle to synthesize three molecules of Ribolose 1,5 bisphosphate into one molecule ribulose 1,5 bisphosphate and five molecules Glyceraldehyde 3 phosphate (G3P). The regeneration of Ribolose1,5 bisphosphate feeds back to replenish the cycle, while G3P is either transported out of the chloroplast and into the cytosol to produce sucrose or stays in the stroma...