An Analysis of Photosynthesis and Energy Transfer in Plants

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PHOTOSYNTHESIS AND ENERGY TRANSFER 3

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The comparison between aerobic respiration and photosynthesis isthat in both processes, there is the production of chemical energyknown as Adenosine Triphosphate (ATP). The difference is that duringaerobic respiration, oxygen and glucose get consumed, while water andcarbon dioxide get produced as the by-products. In photosynthesis,carbon dioxide, water, and light are used, and glucose and oxygen getproduced as the by-products.

The intensity of light affects the rate of photosynthesis. Toillustrate the phenomenon two Elodea plants would be submerged inwater in two separate jars filled with water and one is placed underhigh light intensity and the other one subjected to low lightintensity. Since oxygen get released as a product of photosynthesis,bubbles would rise to the surface of the water. Photosynthesis’rate would be established through counting the number of bubblesreleased after every 60 seconds for ten minutes. The plant placedunder high light intensity is expected to produce more bubbles thanthe one put under low intensity. The rate of photosynthesis is highwhen light intensity is high because light takes less time to reachthe plant and thus get absorbed faster.

In C3 plants, the light reaction takes place in the thylakoidmembrane. The electrons get energized and undergo the electrontransport chain. Water undergoes splitting to form hydrogen andoxygen. The concentration of hydrogen ions inside the thylakoid cellbecomes higher than at the outside causing ATP synthase to occur. ATPenergy then forms when hydrogen passes through the ATP synthase ascarbon dioxide directly enters the Calvin cycle to make sugar. In C4,the mesophyll and bundle sheath cells are the players. Stomata closereducing water loss as the mesophyll cells convert carbon dioxide tooxaloacetate that is consumed in the bundle sheath to generate sugar.

The Krebs cycle takes place in the mitochondria. The components ofelectron transport are contained in the mitochondria`s innermembrane. When acetyl-CoA moves in the Krebs`s cycle, the splittingand recycling of coenzyme A occur. The carbon acetyl elements arethen joined to form carbon dioxide. ATP is generated when citric acidis oxidized after acetyl CoA combines with oxaloacetate. Whenelectrons get subjected to the transport chain, hydrogen ions getpumped across the membrane protein into the inter-membrane space. Thehydrogen ions later diffuse back in the ATP synthase which causes arotor to attach phosphate to ADP resulting in ATP formation.

Membranes regulate the in and out movement of substances in the cell.The phospholipid layer enables selective permeability of the membraneand enhances active as well as passive transport mechanisms. Inmitochondria and chloroplasts, membranes facilitate ATP synthesis viachemiosmosis.

In cellular movement, the cells use cilia and flagellum to propel. ATP burns to power the cell`s locomotion structures. Active transportis responsible for channeling of nutrients in the cell such as themovement of nutrients in the xylem cells. ATP pushes nutrientsagainst concentration gradients and thus facilitates the process.Fermentation causes anaerobic respiration. ATP energy is utilized inthe burning of glucose to form pyruvic acids.