The cell membrane the need for it what is it made up of and its role in allowing passage into and out of it?

Question

little help? i dont really understand.. im not so good at science XD lol thanks in advanve! :)

Answer 1

You can think of a cell as your house.  The walls are the membrane and are there to keep certain things in and other things out.  Permeability describes how selective the membrane is.  Some things like water come into the cell passively like a breeze would come through my window, and other things have to be transported actively and selectively, like if I were to open my door and let my friend in but not let a stranger in.  The passive transport just happens without any work from the cell, but active requires that I get off the couch and open my door.  I know this example is starting to get weird, but hopefully it makes sense!

Answer 2

Psha lies it is saying you aren't good at science, to say you aren't good at science is to say you fail at logic thought, generally a bit a guidance helps though.

The first thought should of course be why would one want a membrane? It serves as a barrier for the cell, much the way you have skin to protect your body. Just as there are things within the environment that would prove deadly to be exposed to if you didn't have skin, lets say E.Bola virus, cells will have similar environmental toxins and such that it must be protected from. The best form of protection is a physical barrier, hence why the cell membrane is needed.

As far as what its made up of very simply its lipids. I don't know what you have covered yet in your science course, but it is made up of a substance that is polar, that means one end is water soluble and one end is insoluble in water.

Role for allowing passage in and out, well we have covered why we need the membrane, its a barrier of protection against the cold harsh reality of the outside world. But the cell has to be able to function and it needs to take in certain substances to survive, food and substances to aid it with growth and all. So it has to allow for these essential items to gain entry into the cell. If you have covered channels and maybe pores even then you are able to explain this rather clearly. Briefly, the membrane allows substances to pass through it by utilizing special proteins that embed within the membrane itself and form a sort of gateway connecting the harsh environment to the soft gentle innards of the cell itself. It also allows certain substances to pass because they can pass through the membrane without need of channels. Generally these will be gasses like oxygen lets say and also hydrophobic substances that can easily pass through the layer. Polar substances however have a hard time passing through the center of the bi-layer

Answer 3

I have some thoughts but I don't remember all that stuff but I would tend to think of it as a filter where the stuff that is meant to stay inside will stay inside and the stuff that is meant to go through it goes through it, this is all controlled by an electric charge.

Answer 4

Typically a bi-layer of lipids, with the hydrophobic ends adjoining.  Pores, some equipped with active pumping mechanisms, move materials in and out of the cell.