This essay will describe the structural and chemical difference between the production and energy storage mechanisms in plant and animal cells. ATP is the compound which provides energy for all plant and animal cells and is used in many processes, such as the production of RNA. The energy produced by ATP molecules is essential for basic bodily functions like muscle contraction. It was discovered in 1929 by Karl Lohmann though its structure was not yet determined. ATP consists of a ribose sugar, an organic base and a string of phosphates. The structural and chemical differences will be discussed followed by the energy storage mechanisms.
There are structural and chemical differences in the production of ATP in plant and animal cells. ATP is the molecule adenosine triphosphate which releases energy through hydrolysis. The ATP molecule loses its third phosphate group in a reaction triggered by the enzyme adenosine triphosphatase. This results in the production of ADP and an inorganic phosphate plus the release of energy. In animal cells, ATP is produced from the breakdown of glucose, which is obtained from food, through glycolysis. Glycolysis always occurs in cellular respiration as it is an anaerobic process; if there is a lack of oxygen respiration stops there any only 2 ATP molecules are produced. If oxygen is present respiration continues to produce more ATP. However in plant cells, ATP is produced from light through photosynthesis in the thylakoids of the chloroplasts and to a lesser extent in the mitochondria. Plant cells produce the majority of their ATP from photosynthesis and only once this method has been exhausted, will they use mitochondria produced ATP.
However, plants can’t always photosynthesise to produce ATP. If there is no light, the calvin cycle occurs. Although this cycle does still require light to an extent since it requires ATP and NADPH which are produced during light dependant reactions. There are three stages to this process, the first is carbon fixation. Carbon fixation is a process in which carbon dioxide is reduced by the addition of hydrogen from NADPH; this is triggered by the enzyme ribulose bisphosphate carboxylase. The purpose of this phase is to make carbon dioxide into an organic molecule. Carbon dioxide reacts with ribulose bisphosphate, a five carbon molecule, to form a 6 carbon molecules. This molecule then splits into two 3 carbon molecules called 3-phosphoglyceric acid (PGA). This results in carbon dioxide becoming an inorganic molecule. The next stage is reduction and requires energy. ATP and NADPH are needed in this stage in order to produce 6 molecules of glyceraldehyde 3-phosphate (G3P) from 6 molecules of PGA. In this step, ATP is converted to ADP and phosphate in order to release energy and NADPH is made into NADP+, losing a hydrogen atom and releasing energy.
The process by which ATP is produced in plant and animal cells is very different. In animals, glucose is...