Animal Cells:
* Cleavage Furrow Formation: The process begins with the formation of a cleavage furrow, a shallow groove on the cell surface.
* Actin and Myosin Involvement: The furrow is driven by a ring of microfilaments made of the proteins actin and myosin. These proteins contract, pulling the plasma membrane inward and constricting the cell.
* Cell Separation: As the furrow deepens, it eventually pinches off the plasma membrane, separating the two daughter cells.
Plant Cells:
* Cell Plate Formation: Instead of a cleavage furrow, plant cells form a cell plate, a new cell wall that divides the cell in two.
* Golgi Apparatus Contribution: The cell plate originates from vesicles produced by the Golgi apparatus, which migrate to the center of the cell.
* Cell Wall Material: The vesicles fuse together and release their contents, which include cell wall material like cellulose and pectin.
* Middle Lamella Formation: As the cell plate grows and fuses with the existing cell wall, it eventually forms the middle lamella, a layer of pectin that cements the two daughter cells together.
Here's a table summarizing the differences:
| Feature | Animal Cells | Plant Cells |
|----------------|-----------------------------------------|---------------------------------------------|
| Mechanism | Cleavage furrow | Cell plate formation |
| Proteins Involved | Actin and Myosin | None |
| Organelle | Not directly involved | Golgi apparatus |
| Cell Wall | Absent | Present, with new cell wall formed |
| Middle Lamella | Absent | Present, forming between daughter cells |
Key Takeaways:
* Animal cytokinesis is driven by contractile proteins, resulting in a pinching off of the membrane.
* Plant cytokinesis involves the construction of a new cell wall from Golgi-derived vesicles.
* These differences reflect the structural variations between animal and plant cells, particularly the presence of a rigid cell wall in plants.
