Describe the ultrastructure of a chloroplast.

Explanation

1. Chloroplast has a double membrane , the outer membrane and the inner membrane separated by a space called periplastidial space.
2. The space enclosed by the inner membrane of chloroplast is filled with gelatinous matrix,lipoproteinaceous fluid called stroma.
3. Inside the stroma there is flat interconnected sacs called thylakoid. The memrane of thylakoid enclose a space called thylakoid lumen.
4. Grana (signular : Granum) are formed when many of these thylakoids are stacked together like pile of coins.
5. Light is absorbed and converted into chemicla energy in the granum, which is used in stroma to prepare carbohydrate.
6. The chloroplast contains osmophilic granules, 70S ribosomes DNA (circular and non histone) and RNA . These chloroplast genome encodes approximately 30 proteins involved in photosynthesis including the components of photosystem I& II ,cytochrome bf complex and ATP synthase, a subunits of Rubisco. It is the major protein component of chloroplast stroma, single most abundant protein on earth .
7. The thylakoid contain small, rounded photosynthetic units called quantosomes.