Is the skin a partially permeable membrane

I’m confused as if it is then surely water molecules would be able to pass as they are small enough but then again they are polar and the cell membrane bilayer is composed of lipids which are non polar but then the hydrophobic heads allow for water to pass in so confused can someone help me

Reply 1

Nitrotoluene

8

Original post by Moon12”

I’m confused as if it is then surely water molecules would be able to pass as they are small enough but then again they are polar and the cell membrane bilayer is composed of lipids which are non polar but then the hydrophobic heads allow for water to pass in so confused can someone help me

Picture the cell membrane as a packed crowd of individuals (the phospholipids). They all have a water-loving head poking out and two water-hating legs tucked in cell membrane, creating a barrier in the middle, where there is not water. The empty space is very thin in the order of thousandths of a micron.
Water molecules, being polar, usually can't make it through that water-less region. But they do have a few tricks to bypass that constraint:
1. Simple Diffusion: Even in the tight density, there are minute openings that appear when individuals move around. Water molecules, being small in size, are able to go through these minute pathways, albeit a slow process, as if moving through a cramped room.
2. Aquaporin Facilitated Diffusion: Visualize aquaporin proteins as doormen with special tunnels the ideal size for water. This allows water to enter and exit quickly without having to deal with the legs. It's a speedy shortcut, permitting cells to regulate their water with ease. Thus, while the membrane tries to keep water out, it's small enough to allow some in, and aquaporins create high-speed lanes for water to move through.

My 2 cents!

(edited 3 weeks ago)

Reply 2

Moon12”

OP

12

Original post by Nitrotoluene

Picture the cell membrane as a packed crowd of individuals (the phospholipids). They all have a water-loving head poking out and two water-hating legs tucked in cell membrane, creating a barrier in the middle, where there is not water. The empty space is very thin in the order of thousandths of a micron.
Water molecules, being polar, usually can't make it through that water-less region. But they do have a few tricks to bypass that constraint:
1. Simple Diffusion: Even in the tight density, there are minute openings that appear when individuals move around. Water molecules, being small in size, are able to go through these minute pathways, albeit a slow process, as if moving through a cramped room.
2. Aquaporin Facilitated Diffusion: Visualize aquaporin proteins as doormen with special tunnels the ideal size for water. This allows water to enter and exit quickly without having to deal with the legs. It's a speedy shortcut, permitting cells to regulate their water with ease. Thus, while the membrane tries to keep water out, it's small enough to allow some in, and aquaporins create high-speed lanes for water to move through.
My 2 cents!

Ooo okay so the skin allows some water molecules thru ??? To summarise thru diffusion as they find openings,

Reply 3

Nitrotoluene

8

Original post by Moon12”

Ooo okay so the skin allows some water molecules thru ??? To summarise thru diffusion as they find openings,

Now you have a perfect understanding of the mechanism.

Is the skin a partially permeable membrane

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