Karthik Ravishankar
Rock Ridge High School
Background Information
Photosynthesis is the process by which plants use water, carbon dioxide, and sunlight and turn it into glucose with a byproduct of oxygen in the chloroplast. Chloroplast is located in the cell membrane of a plant cell. Inside the chloroplast, there are small disks called thylakoids which are located in the stroma of the chloroplast. Stacks of thylakoid cells are called granum. Photosynthesis consists of a Light Dependent Reaction and the Calvin Cycle.
The Light Dependent Reaction (LDR) happen in the Thylakoid Disks. More precisely in the Phospholipid Bilayer of the Thylakoid Disk. First in LDR, light from the sun is absorbed by Photosystem II (PS II). This in turn excites two electrons in PS II. The two electrons jump from PS II and enter Plastoquinone (PQ). The two electrons leave PQ and enter the Cytochrome Complex. The two electrons in the Cytochrome Complex allow H+ ions to enter the Thylakoid Space (Space inside the thylakoid disks) from the Stroma. While this is happening, a process called Photolysis is occurring simultaneously. Photolysis is the process by which water is broken down into oxygen, two H+ ions, and two electrons. The two electrons made from the …show more content…
The first phase of the Calvin Cycle is Carbon Fixation. Carbon dioxide enters the mesophyll layer of plant leaves through the Stomata, pores located on the surface of the leaf. It enters mesophyll cells and then moves into the Stroma. Three carbon dioxide enter the Calvin Cycle one at a time. Each molecule of carbon dioxide is combined to Ribulose Bisphosphate (RuBP), a five carbon sugar. “This reaction is catalyzed by the enzyme RuBP carboxylase/oxygenase, or rubisco.” (3). The added carbon makes a six carbon molecule which is very unstable but splits up into two three carbon molecules called 3-phosphoglyceric acid