How is DNA related to gene and chromosome?

The cell's genetic material, contained in chromosomes within the cell nucleus and mitochondria ... A chromosome contains many genes. A gene is a segment of DNA that provides the code to construct a protein. The DNA molecule is a long, coiled double helix that resembles a spiral staircase.

Chromosomes are primarily composed of DNA ... Basically DNA wraps itself around chromosomal proteins into structures called chromosomes. Genes are units of DNA that have a specific function.