The key difference between monocentric dicentric and polycentric chromosomes is that monocentric chromosomes have one centromere, and dicentric chromosomes have two centromeres while polycentric chromosomes have more than two centromeres.
Chromosomes are thread-like structures composed of DNA and histone proteins. Chromatids, centromeres, chromomeres and telomeres are distinct regions of a chromosome. The centromere is the visible point of constriction in the chromosome which joins sister chromatids together. The centromere is extremely important since it is the chromosomal locus where the kinetochore is formed, and microtubules attach during cell division. Based on the number of centromeres, chromosomes are different types. Monocentric chromosomes have only one centromere. Dicentric chromosomes have two centromeres while polycentric chromosomes have more than two centromeres. Acentric chromosomes, on the other hand, do not have a centromere.
