How is cytokinesis different in plant and animal cells?

Cytokinesis in plant cells involves the formation of a cell plate, while in animal cells, a cleavage furrow forms.

Cytokinesis is the final stage of cell division, following mitosis, where the cytoplasm of a parent cell splits into two daughter cells. However, the process of cytokinesis differs between plant and animal cells due to their structural differences.

In animal cells, cytokinesis begins with the formation of a cleavage furrow. This is a contractile ring made up of actin and myosin filaments that forms around the equator of the cell. As the ring contracts, it pulls the plasma membrane inward, creating a furrow. This furrow deepens and eventually pinches the parent cell into two separate daughter cells, each with its own nucleus and share of cytoplasm, organelles, and other cellular components.

On the other hand, plant cells have a rigid cell wall that cannot be pinched in the way animal cells can. Therefore, they undergo cytokinesis through a different mechanism. Instead of a cleavage furrow, a cell plate forms along the equator of the cell. This cell plate is composed of vesicles from the Golgi apparatus that fuse together at the metaphase plate. These vesicles carry components of the cell wall and membrane. As the vesicles fuse, they form a new cell wall and plasma membrane that grow outward until they reach the existing cell wall. Once this happens, the cell plate is complete, and the parent cell is divided into two daughter cells.

IB Biology Tutor Summary: In summary, cytokinesis differs between plant and animal cells due to structural constraints. Animal cells form a cleavage furrow that pinches the cell into two, using a ring of muscle-like fibres. Plant cells, unable to pinch due to their rigid walls, form a new wall from vesicles that fuse at the cell's centre, effectively splitting the cell into two.