It is neither living nor dead. It is simply not alive the way that any other collection of chemicals is not alive. Is salt alive or dead?
A cell's membrane consists of a collection of chemicals (mainly lipids and proteins). Individual chemicals can never be considered living or dead, any more than rocks or water can be living or dead. While the actual definition of life is tricky, everyone agrees that in order to be alive you need to (at the very least)
Therefore, the cells themselves are alive but the individual parts of the cells are not since they cannot make copies of themselves (this gets complicated when considering some organelles but never mind that here). Similarly, you are alive but your teeth are not. While you can make more of you (you can have children) your teeth cannot make more teeth.
Interesting question to which I don’t know the answer. There is a fair amount of philosophy here: what is ‘alive’? Can you define that?
But let’s at least work the answer from both ends. The plasma membrane surrounds and encapsulates and is part of a living cell. So a cell is clearly living.
The major component of the plasma membrane is a lipid bilayer. You can make an isolated lipid bilayer, and I would consider that to be not living. You could even make a lipid micelle, capacle of surrounding and encapsulating things, and I would not consider the mycelle to be alive.
But plasma membranes are made of more than lipids. They are chock full of proteins as well. I would not consider an isolated protein to be alive, even if functional, nor would I consider it alive stuck into a lipid bilayer. For that matter, if I put all the proteins into the bilayer, I still think I’d consider that ‘alive’, although closer.
So lets work it from the other end. In a living cell, you could kill the cell by removing a limited number of those proteins from the plasma membrane.
I think most biologists would consider that a dead cell, even if the bilayer were still intact.
So I guess, if I had to hazard a guess, I’d say that no, a plasma membrane is not alive in and of itsefl. It is a critical part of something that is alive, the cell.
prove me wrong ;-)
In general the whole cell is the smallest living entity. Isolated pieces of the cell are not considered to be alive. However they are also not “dead”. For something to be dead it is usually necessary that it could also have been alive. The “alive” vs. ”dead” distinction is simply not appropriate.
Well, I guess it would depend if the cell is living or nonliving since the plasma membrane is part of the cell, not the cell itself. It’s like asking if the leg is living or not. It depends on the organism as a whole. Well that’s how I would put it.
I agree with the prior answer. If the cell is alive and well, the plasma membrane can be considered alive. It is part of a cell, and contributes to the life of the cell itself. It is made up of phospholipids, proteins and other substances that aren't necessarily alive on their own, but contribute to the functioning of a healthy living cell.
Plasma Membrane is always living,no matter the cell is living or dead.
It is composed of Lipids and proteins.
The structure of the plasma membrane was best explained in the Fluid Mosaic Model of G.L.Nicholson and S.J.Singer in 1972.
If isolated, it is dead. It cannot not reproduce, eat. Furthermore, it cannot maintain chemical processes necassary for its existence without aid from the cell.
They both the same! Plasma or cell membranes mostly made of a phospholipid by-layer that separates the inner cell contents from the outer environment.
It’s a good question, but I think you need to think of a plasma membrane, not as a rigid structure but as a “fluid “ assembly of many different types of molecules. The main components of the membrane are phospholipid molecules which line up as a double layer, or what is known as the phospholipid bilayer surrounding the cell. Flexibility of the membrane allows the cell to move or squeeze through tight places such as small capillaries or between tight junctions of epithelial cells.
Cell Membrane:-
The cell membrane is a type of plasma membrane that encloses the entire contents of a cell, including the cytoplasm and all the organelles.
The cell membrane is not always the outermost layer of the cell since plant cells also have a cell wall that further encloses the cell membrane.
Animal cells however have no cell wall and the cell membrane is the barrier between the inner contents of the cell and the external environment.
The cell membrane consists of a phospholipid bilayer that also contains integral proteins. Integral proteins often span the membrane and provide pathways for molecules to move through the membrane.
Plasma Membrane:-
The plasma membrane is a membrane that surrounds individual organelles or the contents of a cell. The cell membrane is a type of plasma membrane that encloses the cell.
There are plasma membranes found surrounding both the cytoplasm and contents of a cell and surrounding individual organelles such as chloroplasts and mitochondria.
This means that plasma membranes have several different functions depending on where they are located.
The structure of the membrane can vary depending on what it surrounds, whether that is the entire cell or an organelle in the cell.
A plasma membrane [ https://en.wikipedia.org/wiki/Cell_membrane ](a.k.a. phospholipid bilayer [ https://en.wikipedia.org/wiki/Lipid_bilayer ]) surrounds all biological cells, eukaryotic cell organelles [ https://en.wikipedia.org/wiki/Organelle ]— e.g., the cell nucleus [ https://en.wikipedia.org/wiki/Cell_nucleus ], endoplasmic reticulum [ https://en.wikipedia.org/wiki/Endoplasmic_reticulum ], chloroplasts [ https://en.wikipedia.org/wiki/Chloroplast ], mitochondria [ https://en.wikipedia.org/wiki/Mitochondrion ], and more — as well as intracellular transport vesicles [ https://en.wikipedia.org/wiki/Vesicle_(biology_and_chemistry) ].
All above links refer to Wikipedia [ https://en.wikipedia.org ]entries.
Phospholipid bilayer image courtesy micro.magnet.fsu.edu [ https://micro.magnet.fsu.edu/ ](Plasma Membrane [ https://micro.magnet.fsu.edu/ ])
Nuclear Envelope image courtesy pulpbits.net [ http://pulpbits.net/ ](Animal Cell Nucleus [ http://pulpbits.net/5-animal-cell-nucleus-pictures/animal-nucleus-cell/ ]).
Intracellular transport vesicle image courtesy image.slidesharecdn.com [ http://www.slideshare.net/ravengj/vesicle-transport ](Vesicle Transport [ http://www.slideshare.net/ravengj/vesicle-transport ]).
Mitochondrion image courtesy s-media-cache-ak0.pinimg.com [ https://s-media-cache-ak0.pinimg.com/originals/14/af/47/14af474d678ec27fd0ba768affba9ecf.jpg ](Photosynthesis and Respiration [ https://www.pinterest.com/pin/522487994241036783/ ]).
For much more detail, try search cell membrane (phospholipid bilayer) [ https://www.google.com/search?q=cell+membrane+(phospholipid+bilayer)&oq=cell+membrane+(phospholipid+bilayer)&aqs=chrome..69i57.26374j0j4&sourceid=chrome&ie=UTF-8 ]!
See also animated PowerPoint Cell Membranes — Living Walls .ppsx [ https://app.box.com/s/4v6bn1tjk195vdwykoe3zpfyejh11g5i ].
