Cell structure. Fluorescent light micrograph of cultured cells from a cell line derived from African green monkey kidney cells. Microtubules, part of the cells' cytoskeleton, are red. The cytoskeleton is responsible for intracellular transport, structure and motility of the cell, as well as segregating the chromosomes during nuclear division. Lysosomes, vesicles that contain enzymes for breaking down waste materials, are green.