Question

Differentiate cytokinesis in plant cells and animal cells.

Answer 1

1. Cytokinesis in Plant Cells: Division of the cytoplasm often starts during telophase. In plants, the cytokinesis cell plate grows from the centre towards lateral walls in a centrifugal manner of cell plate formation. Phragmoplast contains microtubules, actin filaments and vesicles from the Golgi apparatus and ER. The Golgi vesicles contain carbohydrates such as pectin and hemicellulose, which move along the microtubule of the phragmoplast to the equator, fuse, forming a new plasma membrane, and the materials which are placed there become a new cell wall. 
   The first stage of cell wall construction is a line dividing the newly forming cells called a cell plate. The cell plate eventually stretches right across the cell, forming the middle lamella. Cellulose builds up on each side of the middle lamella to form the cell walls of two new plant cells.
2. Cytokinesis in Animal Cells: It is a contractile process. The contractile mechanism is contained in the contractile ring located inside the plasma membrane. The ring consists of a bundle of microfilaments assembled from actin and myosin. This fibril helps for the generation of a contractile force. This force draws the contractile ring inward, forming a cleavage furrow in the cell surface, dividing the cell into two.

Answer 2

	Cytokinesis in Plant Cells	Cytokinesis in Animal Cells
1.	Cytokinesis starts during telophase and proceeds by the formation of a cell plate.	Cytokinesis starts during telophase and proceeds by the formation of a cleavage furrow.
2.	The cell plate forms at the centre and grows outward toward the cell walls.	The cleavage furrow forms at the cell periphery and moves inward.
3.	Phragmoplast, containing microtubules, actin filaments, and Golgi-derived vesicles, is involved.	A contractile ring composed of actin and myosin filaments is involved.
4	Golgi vesicles carry pectin, hemicellulose, and carbohydrates to the centre to build the new wall.	Golgi vesicles are not involved in the process.
5.	Vesicles fuse to form a new plasma membrane and the middle lamella, which becomes the cell wall.	The contractile ring generates force, drawing the membrane inward to split the cell.
6.	The cell wall is formed between the two daughter cells.	The plasma membrane pinches in to divide the cell into two daughter cells.
7.	The process is centrifugal – it proceeds from the centre to the periphery.	The process is centripetal – it proceeds from the periphery to the centre.