UPSC Civil Services Model Paper 7

Plastids are a group of phylogenetically and physiologically-related organelles found in all types of plants and algae. Hence statement 1 is not correct.
Different types of plastids contribute to plant metabolism thus promoting plant growth and development.
They have a double membrane .
There are several small coloured bodies in the cytoplasm of the cells of Tradescantia leaf.
They are scattered in the cytoplasm of the leaf cells.
They are self-replicating.
Hence statement 3 is correct.
They are of different colours . Some of them contain a green pigment called chlorophyll.
Green coloured plastids are called chloroplasts.
They provide green colour to the leaves.
Chloroplasts are important for photosynthesis in plants.
Chloroplasts also contain various yellow or orange pigments in addition to chlorophyll.
Plastids are present only in plant cells.
There are two types of plastids: chromoplasts (coloured plastids) and leucoplasts (white or colourless plastids).
Hence statement 4 is correct.
Leucoplasts are primarily organelles in which materials such as starch, oils and protein granules are stored. Hence statement 2 is correct.
The internal organization of the plastids consists of numerous membrane layers embedded in a material called the stroma.
Plastids are similar to mitochondria in external structure.
Plastids also have their own DNA and Ribosomes.