Define the following terms: cell, prokaryotic cell, eukaryotic cell, organelle.

(I) Cell: Cell is the basic building units of an organism.

(ii) Prokaryotic cell: A Prokaryotic cell is primitive in organisation. It has a nucleoid (nuclear membrane is absent).

(iii) Eukaryotic cell: A cell having membrane bound cell organelles are called eukaryotic cell.

(iv) Organelle: Small membrane bound structures within a cell are called organelles. Example: Nucleus, mitochondria, lysosomes.