<P> Chromosomes in eukaryotes are composed of chromatin fiber . Chromatin fiber is made of nucleosomes (histone octamers with part of a DNA strand attached to and wrapped around it). Chromatin fibers are packaged by proteins into a condensed structure called chromatin . Chromatin contains the vast majority of DNA and a small amount inherited maternally, can be found in the mitochondria . Chromatin is present in most cells, with a few exceptions, for example, red blood cells . </P> <P> Chromatin allows the very long DNA molecules to fit into the cell nucleus . During cell division chromatin condenses further to form microscopically visible chromosomes . The structure of chromosomes varies through the cell cycle . During cellular division chromosomes are replicated, divided, and passed successfully to their daughter cells so as to ensure the genetic diversity and survival of their progeny . Chromosomes may exist as either duplicated or unduplicated . Unduplicated chromosomes are single double helixes, whereas duplicated chromosomes contain two identical copies (called chromatids or sister chromatids) joined by a centromere . </P> <P> Eukaryotes (cells with nuclei such as those found in plants, fungi, and animals) possess multiple large linear chromosomes contained in the cell's nucleus . Each chromosome has one centromere, with one or two arms projecting from the centromere, although, under most circumstances, these arms are not visible as such . In addition, most eukaryotes have a small circular mitochondrial genome, and some eukaryotes may have additional small circular or linear cytoplasmic chromosomes . </P> <P> In the nuclear chromosomes of eukaryotes, the uncondensed DNA exists in a semi-ordered structure, where it is wrapped around histones (structural proteins), forming a composite material called chromatin . </P>

Where are chromosomes found in multi cellular organisms