Write the help of a labelled diagram describe the structure of a chloroplast.

Chloroplasts are present in green algae and higher plants. They are greenish plastids which possess photosynthetic pigment called chlorophyll. Chloroplasts take part in the synthesis of food, hence, they are known as kitchen of the cell.

Each chloroplast is bounded by two unit membranes. The inside of the chloroplast is filled with dense homogenous matrix called stroma. Stroma contains a variety of photosynthetic enzymes, starch grains, DNA and ribosomes. In the stroma, flattened thread-like structures called thylakoid are present. The thylakoids are stacked over one another to form granum (plural-grana). Granum is the site of light reaction during photosynthesis while stroma is the site of dark reaction during photosynthesis.