Taking a Look at Photosynthesis

870 Words Jan 31st, 2018 4 Pages
Chloroplasts are large and a mature leaf may contain 20-100. They are described as flattened spheres. New plant cells contain smaller organelles that contain proplastids that can develop into different forms of plastids. For example, amyloplasts are used to store starch, while chromoplasts create pigments for fruits and flowers. Chloroplasts contain chlorphyll which contain the green pigment observed in plants. The membranes within the chlorplast are importnat in the function of photosynthesis. Chloroplasts have an outer and inner membrane that are separated by an intermembrane space. The inner membrane contains stroma, a gel-like matrix filled with enzymes for C, N, and S reduction and assimilation. The outer membrane contains porins that allow solutes with a molecular weight of a maximum of 5000 to pass. The inner membrane transport proteins regulate the flow of metabolites between the inner membrane and intermembrane space. Thylakoids are the chloroplasts third membrane, which are flat, sac like structures within the stroma arranged in stacks called grana. The grana are connected by stroma thylakoids. The thylakoid lumen surrounfs the grana and stroma thylakoids. The thylakoid membrane is a semipermeable barrier which allows for the development of electrochemical proton gradient between the lumen and stroma. Photosynthetic bacteria do not contain chloroplasts. For example, in cyanobacteria, the…

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