Question

How do neutral solutes move across the plasma membrane? Can polar molecules also move across it in the same way?

Answer 1

YES

Answer 2

will you plz explain me the mechanism

Answer 3

w8

Answer 4

ok

Answer 5

Theres a few methods of membrane transport - passive and active. Theres various pumping mechanisms to pump ions into and out of the cell

Answer 6

Polar molecules have certain charged regions. These charges aren't really happy when they try to go through the lipid middle portion of the Plasma membrane. Thus why we generally say polar molecules don't "Freely permeate" through the PM.

Neutral molecules on the other hand, are quite happy to pass through the lipid middle portion of the PM, thus we say that they are generally "permeable".

However, polar/charged molecules do enter the cell. Many polar molecules enter the cell by "transport": they don't just flow across the PM, they must be helped a bit. Usually, there is a transport protein, which can best be described as a tube. The inside of the tube has charges, creating a hydrophilic (~polar) environment. Polar molecules can then enter the cell.

There are many transport mechanisms -- way too numerous to explain. Some transport proteins are like tubes, others are like revolving doors, others are like funnels which flip inside out.

Answer 7

i am going to assume you have some education in chemistry and are currently taking a highschool biology course so that i may more accurately describe the mechanisms that cause nonpolar molecules to move more freely across a lipid bilayer than polar molecules. nonpolar molecules and polar molecules are hydrophobic and hydrophilic, respectively. this means that polar molecules are more attracted to the polar water molecules on either side of the lipid bilayer than the lipids themselves. hydrophobic molecules on the other hand are not attracted to the polar water molecues any more than they are attracted to the lipid bilayer, this allows the molecules to freely enter the lipid region and cross to the other side.

it is for this reason that cells often require passive and active(not requiring and requiring ATP, respectively) transport proteins to assist in the movement of polar and charged particles across the membrane.

Answer 8

Sorry i didn't understand this part: "hydrophobic molecules on the other hand are not attracted to the polar water molecules any more than they are attracted to the lipid bilayer" Which are the hydrophobic molecules? I thought molecules are neutral and charged (polar). If water is neutral/slightly polar how can water molecules freely pass the lipid bilayer? Is it that water molecule attracted by the polar inner side of the membrane can overcome the hydrophobic inner part? Then what about oxygen which is for sure non polar? And if this is all true - than why charged particles cannot pass due to attraction as well and are supposed to pass through protein channels?