Bio 240 – Photosynthesis & Respiration
Photosynthesis & RespirationJennifer StevensBIO/240May 8, 2016Dr. Xavier VillarrealPhotosynthesis & Cellular RespirationIn plant and animal cells, creating energy is crucial to the organism’s survival. Ensuring that the right raw materials are present to start the process of creating energy is important, just as ensuring that both types of cells are present in an ecosystem to ensure survival of each. For plant cells, photosynthesis is used to convert sunlight and carbon dioxide into energy. In animal cells, cellular respiration is used to convert oxygen and complex sugars into energy. PhotosynthesisPhotosynthesis is the process where plants use sunlight to make energy. The light energy from the sun is changed into chemical energy through photosynthesis to help the plant survive, reproduce, and make their own food (also known as photoautotroph). Through photosynthesis, organisms take the sunlight, carbon dioxide, and water to create energy and the byproduct oxygen. There are two types of reactions in photosynthesis: light dependent and light independent reaction (Reese, 2012).
Light Dependent ReactionLight dependent reaction can be seen taking place during the daytime, when the sunlight is available for use. In this reaction, the chlorophyll inside chloroplasts of plants utilizes the light energy from the sunlight in the photosynthesis process, which gives this reaction its name. Chemical energy is converted from light energy to produce NADPH and ATP (Schmit, 2010).Light Independent ReactionLight independent reactions, also known as the Calvin Cycle, occur without the need of sunlight for light energy for the organism to produce chemical energy. This means that this reaction can occur in total darkness. Instead, the organism takes carbon dioxide and other molecules and converts them into glucose and creating the byproduct oxygen. The reactions occur in the stroma in the chloroplast (Schmit, 2010).Cellular RespirationCellular respiration is a chemical process in which the most energy in a cell is created. This is used to create most of the molecules required to create the chemical energy needed for an organism to function. Within the cell, the energy is taken from the ATP. Within cellular respiration, there are three main stages (Govindjee., 2006).GlycolysisThe first stage in cellular respiration is glycolysis. In this stage, the six complex carbon-sugar compounds are broken down into three simple sugars: pyruvic acid and two ATP molecules. This stage occurs with oxygen (aerobic respiration) or without oxygen (anaerobic respiration).