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Chloroplasts have their own genome, which encodes a number of thylakoid proteins. However, during the course of plastid evolution from their cyanobacterial endosymbiotic ancestors, extensive gene transfer from the chloroplast genome to the cell nucleus took place. This results in the four major thylakoid protein complexes being encoded in part ...
H + ions from the lumen of the thylakoid into the cytosol of a cyanobacterium or the stroma of a chloroplast. A steep H + gradient is formed, which allows chemiosmosis to occur, where the thylakoid, transmembrane ATP-synthase serves a dual function as a "gate" or channel for H + ions and a catalytic site for the formation of ATP from ADP + a PO ...
The structure and function of cytochrome b 6 f (in chloroplasts) is very similar to cytochrome bc 1 (Complex III in mitochondria). Both are transmembrane structures that remove electrons from a mobile, lipid-soluble electron carrier (plastoquinone in chloroplasts; ubiquinone in mitochondria) and transfer them to a mobile, water-soluble electron ...
Stroma, in botany, refers to the colorless fluid surrounding the grana within the chloroplast. [1] Within the stroma are grana (stacks of thylakoid), the sub-organelles where photosynthesis is started [2] before the chemical changes are completed in the stroma. [3] Photosynthesis occurs in two stages.
Two families of reaction centers in photosystems can be distinguished: type I reaction centers (such as photosystem I in chloroplasts and in green-sulfur bacteria) and type II reaction centers (such as photosystem II in chloroplasts and in non-sulfur purple bacteria). The two photosystems originated from a common ancestor, but have since ...
Indeed, the chloroplast of the chromists is located in the lumen of the endoplasmic reticulum instead of in the cytosol. Moreover, only chromists contain chlorophyll c . Since then, many non-photosynthetic phyla of protists, thought to have secondarily lost their chloroplasts, were integrated into the kingdom Chromista.
Cross section of the gut. The lumen is the space in the middle also known as the volume. Normal histology of the breast, with lumen annotated at bottom right [1] In biology, a lumen (pl.: lumina) is the inside space of a tubular structure, such as an artery or intestine. [2]
In photosynthesis, plastocyanin functions as an electron transfer agent between cytochrome f of the cytochrome b 6 f complex from photosystem II and P700+ from photosystem I. Cytochrome b 6 f complex and P700 + are both membrane-bound proteins with exposed residues on the lumen-side of the thylakoid membrane of chloroplasts. Cytochrome f acts ...