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8.4 describe the stroma as matrix lying within the inner membrane containing DNA, ribosomes, lipid droplets and starch granules
describe the stroma as matrix lying within the inner membrane containing DNA, ribosomes, lipid droplets and starch granules
- The matrix of the chloroplasts is called the stroma. It is electron dense and contains circular DNA and ribosomes.
- The stroma also contains lipid droplets and starch granules. The starch granules are formed from the products of photosynthesis.
- In higher plants, the chloroplast genome codes for twenty chloroplast proteins, several proteins that are part of photosystems I and II, subunits of ATP synthase and other proteins used in the chloroplast. The genes also code for about 40 proteins with unknown functions. The similarities between chloroplast and bacteria genomes indicate that chloroplasts arose from photosynthetic bacteria as the endosymbiotic hypothesis suggests. The chloroplast genome has remained unchanged for at least several hundred million years.