The cell wall or membrane.
Cell
Try cell wall for an answer.
Cell wall
stiff part in a plant cell
Membranes do not have a stiff outside. I suspect the answer you are looking for is the cell wall, which is a stiff structure found outside the cell membrane of a plant cell, but separate from it.
The cell wall
to provide structure for the cell, mainly through "turgor pressure" against the cell wall. this keeps the plant stiff.
The still part of a plant cell is called Cell Wall. This is the rigid outermost layer of a plant cell. It makes the cell stiff -providing the cell with mechanical support - and giving it protection. It is found just inside the cell wall and is made up of complex lipids (fats) and proteins.
Cell wall
Cell Wall
Membranes do not have a stiff outside. I suspect the answer you are looking for is the cell wall, which is a stiff structure found outside the cell membrane of a plant cell, but separate from it.
If you are someone who tends to easily break electronic items including cell phones, getting a tough cell phone may be a good idea. PC Magazine has a list of the top 10 most rugged cell phones available. http://www.pcmag.com/article2/0,2817,2381435,00.asp