Question

Draw a well labelled diagram of structure of choroplast .

Answer 1

Ultrastructure of chloroplast:

• Chloroplasts in higher plants are oval or disc shaped.
  
• They are 10 micro meter in length and 2 to 4 micro meter in diameter.
• Chloroplasts have double membrane envelop, an outer membrane and an inner membrane. The space between the two membrane is called as inter-membrane space.
• The inner amorphous mass of chloroplast is called as stroma. Small granule like structures called grana are suspended in the stroma.
• Each grana are 0.5 to 2 micrometer in diameter and each chloroplast more than 50 grana.
• Grana are made of flat structures called thylakoids stacked together, the inner space of thylakoids is called as thylakoid space and these thylakoids are stacked with the help of a membrane called stroma lamellae.
• From inside the thylakoids small spherical structures emerge into stroma, and these structures contain a protein called CF1 which play an important role in the formation of ATP.
• The stroma comprises of fine grains which are mainly starch grains or lipid granules which serve as lipid reservoir for the formation of thylakoid membrane.

Functions of chloroplasts:

• Chloroplasts are the site where photosynthesis takes place.
• They carry out light dependent and light independent mechanisms which convert solar energy into chemical energy.