Question

What is a cleavage furrow?

Answer 1

Hint: Cell division consists of two processes cytokinesis (cytoplasmic division) and karyokinesis (nuclear division). Cytokinesis is the mechanism through which the cytoplasm of a single eukaryotic cell splits into two daughter cells during cell division. In mitosis and meiosis, cytoplasmic division occurs during or after the late phases of nuclear division and is accounted for the formation of a cleavage furrow.

Complete answer:
At the cell division site, the cleavage furrow is a plasma membrane invagination. The cleavage furrow starts off as a shallow groove before deepening to split the cytoplasm.
Actin and myosin, the proteins responsible for muscle contraction, start the process of generating the cleavage furrow, resulting in an actomyosin ring. The mechanism also involves other cytoskeletal proteins and actin binding proteins.
The contractile ring, a ring of actin microfilaments that develops during early anaphase, causes animal cell cleavage furrow development. Concentrated microfilaments and actin filaments are prominent in the contractile ring area, indicating the presence of myosin.
The contractile ring tightens around the cell's cytoplasm during cellular cleavage, pinching the cytoplasm into two daughter cells.
Therefore, Cleavage furrow is the invagination of plasma membrane followed by accumulation of various proteins, microfilaments and regulators at the site of invagination which aids in the completion of cytokinesis.

Note:
A cell's life cycle is referred to as the cell cycle. The stages of the cell cycle of eukaryotic cells, or cells with a nucleus, are split into two major phases: interphase and mitotic (M) phase. During interphase, the cell divides and duplicates its DNA. During the mitotic (M) phase, the cell splits its cytoplasm and divides its DNA into two sets, resulting in the formation of two new cells.