Analysis of Photosynthesis Process - Essay Example

 6H2O + 6CO2 ----------> C6H12O6+ 6O2Chloroplasts are made up of thylakoid membranes where the green pigment chlorophyll is found. Chlorophyll looks green because it absorbs the red and blue wavelength of the visible light spectrum, reflecting the green.

The molecule is made up of a porphyrin ring with several carbon and nitrogen bonds and a magnesium ion in the center (Starr et al., 2009). The first part of photosynthesis is the light-dependent reaction occurring in the thylakoid membrane. Here chlorophyll and other accessory pigments like beta carotene absorb different wavelengths of light in the antenna complex (Starr et al., 2009). When one chlorophyll pigment absorbs a photon of light in photosystem II, the molecule reaches a higher energy state, exciting its electron.

This excitation results in the loss of one electron which is then passed down the electron transport chain via electron carriers. The excited electron is transferred to another chlorophyll molecule in photosystem I creating a proton gradient. The transfer of electrons results in the reduction of co-enzyme NADP to NADPH (Starr et al., 2009). The created energy also helps hydrogen ions to move across the thylakoid membrane. Also at the end of the proton gradient, the enzyme ATP synthase converts ADP to ATP by a process called photophosphorylation where the converted light energy will be stored (Starr et al., 2009). A water molecule is also split through the process of photolysis resulting in an oxygen molecule and allowing the chlorophyll pigment to regain its lost electron.

Therefore, at the end of the first cycle, the resulting molecules are 3 ATP, 1 oxygen, and 2 NADPH (Starr et al., 2009). The second part of the process is called the light-independent reaction and occurs in the stroma within the chloroplasts and is used to take the carbon dioxide molecule and convert it into sugar. Although it doesn’t need light, this part of photosynthesis relies on the products ATP and NADPH to drive its process, the Calvin cycle. The enzyme RuBisCO takes the carbon dioxide molecule and uses it to catalyze RuBP (Starr et al., 2009). The carbon dioxide combines with this 5-carbon molecule in a process called carbon fixation and produces 2 molecules of 3PG. These two 3PG molecules are converted by ATP into a 3-carbon sugar (G3P) in the reduction phase by adding on a phosphate group, producing ADP (Starr et al., 2009).