AP BIOLOGY

Detailed explanation-1: -In many animal cells, actomyosin filaments assemble at the cleavage furrow, often forming an annular structure known as the “contractile ring” (Fig.

Detailed explanation-2: -In animal cells and many unicellular eucaryotes, the structure that accomplishes cytokinesis is the contractile ring-a dynamic assembly composed of actin filaments, myosin II filaments, and many structural and regulatory proteins.

Detailed explanation-3: -Cytokinesis is the last step of cell division that partitions the cellular organelles and cytoplasm of one cell into two. In animal cells, cytokinesis requires Rho-GTPase-dependent assembly of F-actin and myosin II (actomyosin) to form an equatorial contractile ring (CR) that bisects the cell.

Detailed explanation-4: -Cytokinesis in animal and plant cells. Cytokinesis in an animal cell: an actin ring around the middle of the cell pinches inward, creating an indentation called the cleavage furrow. Cytokinesis in a plant cell: the cell plate forms down the middle of the cell, creating a new wall that partitions it in two.

Detailed explanation-5: -Mitosis is usually accompanied by cytokinesis, during which the cytoplasmic components of the daughter cells are separated either by an actin ring (animal cells) or by cell plate formation (plant cells).