Write a note on plastids and nucleus of a cell. [3 MARKS]
Each point: 1.5 Mark
1. Plastids are a major organelle found in the cells of plants and algae. Plastids are the site of manufacture and storage of important chemical compounds used by the cell. They often contain pigments used in photosynthesis and the types of pigments present can change or determine the cell's colour. They are of different colours. Some of them contain green pigment called chlorophyll. Green coloured plastids are called chloroplasts.
2. Nucleus acts as control centre of the activities of the cell. The entire content of a living cell is known as protoplasm. It includes the cytoplasm and the nucleus. Protoplasm is called the living substance of the cell. Nucleus contains thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of characters from the parents to the offspring. Genes have all the information to carry out all the processes of the cell.