A '''chromosome''' (literally: ''colored body'', from [[Greek]]) is a packaged unit of [[DNA]] and associated proteins.<ref>http://learn.genetics.utah.edu/units/disorders/karyotype/whatarechrom.cfm</ref> The chromosome carries portions of the hereditary information of an organism. The DNA is tightly coiled many times around proteins called [[histone]]s that support the chromosome structure.<ref>http://ghr.nlm.nih.gov/handbook/basics/chromosome</ref> The bound DNA units are called [[nucleosome]]s. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two [[sex chromosomes]]. Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.
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A '''chromosome''' is a packaged unit of [[DNA]] and associated proteins.<ref>http://learn.genetics.utah.edu/units/disorders/karyotype/whatarechrom.cfm</ref> The chromosome carries portions of the hereditary information of an organism. The DNA is tightly coiled many times around proteins called [[histone]]s that support the chromosome structure.<ref>http://ghr.nlm.nih.gov/handbook/basics/chromosome</ref> The bound DNA units are called [[nucleosome]]s. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two [[sex chromosomes]]. Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.