Chromatin is a strand of DNA wrapped around a protein, and is a building block of all chromosomes. The chromosome is the structure in which DNA is stored in cells.
Chromosomes are the basic way in which DNA is stored in cells. Different living things have different numbers of chromosomes, but all living things have DNA stored in chromosomes. Within the cell, the chromosomes themselves are stored in the cell nucleus. The number of chromosomes in a cell determines how the cell functions, and changes in the number of chromosomes can have dramatic effects on the plant or animal the cell is a part of. A common example of this is Down syndrome, which is caused by a person having three copies of chromosome 21, rather than two.
A chromatin is a single strand of DNA wrapped around a protein. During the process of cell division and DNA replication, chromatin are copied and then combined into whole chromosomes. Each individual chromosome consists of a pair of two chromatin. The chromatin are joined at the centromere to form a chromosome. The process of DNA replication and construction by creating and combining new chromatin is essential to the growth and maintenance of all living creatures.