What is the function of the lipid bilayer in a cell membrane?

Question

Accepted Answer

Hi, everybody. Let's take a look at the next question, which of the following best describes the role of the lipid bilayer in maintaining the internal environment of the cell. And so let's look through our four answer choices here, evaluating each of them as we do. So we don't have to read them all and then read them all again. So we're thinking about that lipid fly layer that makes up the cell membrane and how does it maintain a specific internal environment in the cell? So first, we have choice a saying that it acts as a rigid wall that prevents any substances from entering or leaving the cell. Well, this one hopefully is pretty easy to rule out. We know that it's not rigid, it's fluid and flexible. And this is important because this allows cell growth and division. In addition, it allows the distribution of membrane proteins because they can kind of move around in this fluid environment of the lipid bilayer. And then of course, the lipid bilayer does not prevent any substance from entering or leaving the cell. It prevents some substances from entering or leaving the cell because a key characteristic of the lipid bilayer is that it's a selectively permeable membrane. And that ob obviously really important in maintaining the internal environment of the cell because it has control over what enters or leaves the cell to have control over what that internal environment is. So choice. A definitely wrong then B says allows all substances to freely pass in and out of the cell without regulation. Again, we just talked about selective permeability. So this one's obviously wrong. It allows some substances to pass freely, but it absolutely regulates what goes in and out of the cell since it is a membrane that only allows certain things to go in and out and controls how they do. So then we move on to choice. C collectively permits the passage of certain molecules while blocking others. And this is of course correct. Just as we discussed, it can allow the passage of certain molecules. Few things can just diffuse through. But more often there are things like channels, protein channels, protein carriers that bring molecules across. Now to be thorough. Let's just look at choice D generates energy for the cell by facilitating chemical reactions. Well, this one is incorrect, you might pause on it for a moment because we can recall that in procaryotic cells, we have electron transport chain proteins embedded in the membrane, but this is not facilitating chemical reactions itself. That would be enzymes that do that the cell membrane itself doesn't generate any energy. So choice D incorrect. So once again, our correct answer here to best describe the role of the lipid bilayer in maintaining the internal environment of the cell. Is choice c it selectively permits the passage of certain molecules while blocking others. See you in the next video.

What is the function of the lipid bilayer in a cell membrane?

Verified video answer for a similar problem:

Key Concepts

Lipid Bilayer Structure

Cell Membrane Function

Fluid Mosaic Model