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How is NADPH produced in (a) Photosynthetic AND (b) Non-photosynthetic cells? How and where are ketone bodies (a) synthesised AND (b) utilised?
NADPH is used in the Calvin cycle, which takes place in the stroma of chloroplasts and synthesises hexoses from carbon dioxide and water. In order to oxidise NADPH by this process, ribulose 5-phosphate is first phosphorylated by R5P kinase to generate ribulose-1,5-bisphosphate. This is carboxylated and broken down by CO2 to give two molecules of 3-phosphoglycerate in a reaction catalysed by the enzyme Rubisco, and which features two intermediates ? one highly unstable and the other an enediolate. The enediolate forms first as the ketone group on R-1,5-BP is reduced, before carboxylate adds to form the unstable intermediate which immediately breaks down via hydrolysis to give two 3-phosphoglycerates.
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whereas eukaryotic cells, if they have a cell wall, have one made of cellulose[c]. Prokaryotic cells may also have a slimy capsule around the cell for protection. Genetic material Another major difference between the two types of cell is that prokaryotic cells do not have a nucleus or other membrane bound organelles whereas eukaryotic cells do ? instead the genetic material of prokaryotes (a single plasmid [d]as opposed to several chromosomes) is in a region of the nucleus called the nucleoid. The genetic material in eukaryotic cells is associated with the histone protein, whereas that of prokaryotic cells is folded around several different proteins including the HU protein.
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