Write one functions of each type …

• Plastid is a membrane-bound organelle found in the cell of plants, algae and few eukaryotic cells.
• It the site of production and storage of important chemical compounds which are used by the cells of autotrophic organisms.
• They contain pigments which are used in photosynthesis and the types of pigments determine the cell's colour.
• The types of plastids are-

1) Chloroplasts:- are the green plastids which contain chlorophyll pigments for photosynthesis.

2) Chromoplasts:- are the coloured plastids for pigment synthesis and storage.

• The pigment present in them is carotene which gives a different colour to fruits and flowers.

3) Gerontoplasts:- are the chloroplasts that are going through the ageing process.

• These are present in the leaves in which no more photosynthesis occurs (such as in the fall months).

4) Leucoplasts: are the colourless plastids for monoterpene synthesis found in non- photosynthetic parts of the plants.

• They are of three types:- 

a) Amyloplasts- stores starch.

b) Proteinoplasts-  stores proteins.

c) Elaioplasts- stores fats and oils.