DNA, RNA, Chromosomes, and Genes


What is the difference between a gene and a chromosome?

The human genome contains twenty-four distinct, physically separate units called chromosomes. Arranged linearly along the chromosomes are tens of thousands of genes. The term “gene” refers to a particular part of a DNA molecule defined by a specific sequence of nucleotides. It is the specific sequence of the nitrogen bases that encodes a gene. The human genome contains about three billion base pairs, and the length of genes varies widely.


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