Homologous chromosomes are similar in size and shape. they have the same genes and originate from different parents. Sister chromatids are found in replicated and contain exact copies of the single double helica; molecule of DNA.
Actually homologous chromosomes can be defined as the chromosomes same in shape and size, and carry the genes of contrasting chaacteristics..Chromatids whic separate in metaphase of cell division are sister chromatids.