AP BIOLOGY

Detailed explanation-1: -During cytokinesis in animal cells, a ring of actin filaments forms at the metaphase plate. The ring contracts, forming a cleavage furrow, which divides the cell in two. In plant cells, Golgi vesicles coalesce at the former metaphase plate, forming a phragmoplast.

Detailed explanation-2: -Formed during cytokinesis, the last step of cell division, the contractile ring is composed of filamentous actin (F-actin) and the motor protein myosin-2, along with additional structural and regulatory proteins.

Detailed explanation-3: -Animal cell cleavage furrow formation is caused by a ring of actin microfilaments called the contractile ring, which forms during early anaphase. Myosin is present in the region of the contractile ring as concentrated microfilaments and actin filaments are predominant in this region.

Detailed explanation-4: -In fungal, amoeboid and animal cells, during the cytokinesis at the end of cell division, a cleavage furrow forms in the plasma membrane. A contractile ring containing actin and myosin is assembled at the selected site of the future cleavage furrow.

Detailed explanation-5: -The contractile ring is a ring-shaped structure located just beneath the plasma membrane at the future division site in many, though not all, eukaryotic cell types. Composed of actin, myosin and many other proteins, it assembles in anaphase and contracts as cells divide.