Q.Draw a neat labelled diagram of chloroplast.

A chloroplast is a double-membraned plastid whose internal thylakoid membranes (grana + stroma lamellae) carry out the light reactions, while the enclosing stroma carries out the dark reactions (Calvin cycle) of photosynthesis.

Labelled structure of a chloroplast (described, as no image tool is available here):

1. Outer membrane - the smooth, permeable boundary membrane of the chloroplast.
2. Inner membrane - lies just within the outer membrane; less permeable, regulates passage of materials into the stroma.
3. Intermembrane space - the narrow space between the outer and inner membranes.
4. Stroma - the proteinaceous ground matrix enclosed by the inner membrane; contains the enzymes of the Calvin cycle (dark reactions), circular chloroplast DNA, 70S ribosomes, and starch grains.
5. Thylakoids - flattened, membrane-bound sac-like structures suspended in the stroma; their membranes contain chlorophylls, carotenoids and the photosystems (PS I and PS II) that carry out the light reactions.
6. Grana (singular: granum) - stacks of thylakoids, resembling a pile of coins, connected to one another.
7. Stroma lamellae - flat membranous tubules that interconnect the thylakoids of different grana, maintaining connectivity between grana stacks. …