-Coiled thread-like structures that are formed in the nucleus
-They are so called because they take up certain basic stains very readily
-Can only be seen in a dividing cell i.e. during cell division
-Consists of proteins and DNA
-Consist of definite member in each cell
-E.g. in fruit fly, drosophila, there are 8, and in man there are 46 chromosomes
-Chromosomes exist in pairs
-The member of each pair are called homologous chromosomes
-Each chromosome is able to reproduce itself