What is a cleavage furrow?

A cleavage furrow is a specialized structure that forms during cell division, particularly during the process of cytokinesis. Cytokinesis is the final step of cell division, where the cytoplasm of a parental cell is divided into two daughter cells. This process occurs after the nuclear division (either mitosis or meiosis) has taken place.

During cytokinesis in animal cells, a cleavage furrow appears as a shallow groove or crease on the cell surface. It marks the site where the cell membrane is being pinched inward. The formation of the cleavage furrow is essential for separating the two daughter cells. The process begins with the contraction of a ring of actin and myosin filaments just beneath the cell membrane. These filaments contract, pulling the membrane tighter and tighter until the cell is pinched into two distinct daughter cells.

In contrast to animal cells, plant cells have a different mechanism of cytokinesis. Plant cells have a rigid cell wall that prevents the formation of a cleavage furrow. Instead, a structure called the cell plate forms in the middle of the cell, and it gradually develops into a new cell wall that separates the two daughter cells.