Where sister chromatids are attached. when nuclear material is duplicated. a groove at the cell surface located between dividing animal cells. a protein structure attached to the centromere. fusion of an egg with more than one sperm. chromosomes that have the same set of genes, one from the mother and one from the father. microtubule organizing center. a membrane structure located between dividing plant cells. a cell with two nuclei. a microtubule structure in animal centrosomes. reciprocal exchange of genetic material between non-sister chromatids