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Chromosomes
Cell structures found in all biological cells that contain deoxyribonucleic acid (DNA) and DNA-bound proteins. Chromosomes contain single pieces of DNA molecules in the form of genes. Each cell nucleus contains 46 chromosomes organized in 23 pairs. The mother donates one member of a chromosome pair, and the father donates the other member of the chromosome pair. Therefore, the two members of a chromosome pair are not identical. Geneticists have numbered these chromosomes from the largest to the smallest.