Cloroplasts | definition of Cloroplasts by Medical dictionary
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the photosynthetic unit of a plant cell, containing all the chlorophyll.
A plant cell inclusion body containing chlorophyll; occurs in cells of leaves and young stems. Site of photosynthesis in higher plants.
[chloro- + G. plastos, formed]
Fig. 101 Chloroplast . (a) Thin section through a whole chloroplast. (b) Thylakoid arrangement. (c) An enlarged section of a granum.
chloroplast a type of PLASTID containing CHLOROPHYLL found within the cells of plant leaves and stems. The chlorophyll is packed within granules called quantasomes which are located in the walls of flattened sacs called LAMELLAE or thylakoids. The lamellae lie closely together in certain areas to form grana and are more separate in the intergranal regions. LIGHT REACTIONS of photosynthesis are thought to take place in the quantasomes while DARK REACTIONS occur in the watery matrix surrounding the lamellae, the stroma.