Q. How does the plant cell wall act in response when it is placed under hypotonic medium?
The plant cell wall (the covering of the cell external to the cell membrane) is made of a polymer of glucose, cellulose.
When the cell is put under hypotonic medium it absorbs lots of water through osmosis. In that situation the cell wall pressure acts to compensate the osmotic pressure thus forbidding excessive enhance of the cellular volume and the cell lysis.