Cytoplasm
The cell membrane. It's called a bi-layer, and contains two layers of phospholipids. The tails interact with one another while the heads interact with the aqueous solution.
A phospholipid bilayer is a two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward. Also called lipid bilayer.http://dictionary.infoplease.com/phospholipid-bilayer
A double layered fluid structure containing sort of loose but contained things such as proteins, cholesterol molecules, etc. It has a hydrophobic layer of longer apolar lipid chains sandwiched in between two hydrophilic (polar) lipid edges.
A double layered fluid structure containing sort of loose but contained things such as proteins, cholesterol molecules, etc. It has a hydrophobic layer of longer apolar lipid chains sandwiched in between two hydrophilic (polar) lipid edges.
The cell plasma membrane is made of bipolar fatty acids with the fatty (uncharged) hydrophopic part pointed towards the inside of the plasma membrane and the hydrophillic (charged) part facing the inside of the cell or the outside of the cell.
All the molecules in the bilayer are in a low energy state, so are stable on a molecular level. The layer is kept stable because the phosphate head is attracted to the water while the lipid is repelled. This lines up the molecules. They have no reason to move. In a bilayer, the molecules are back to back, so lipids are trapped in a hydrophobic section.
I think that we must have the same textbook because I had the same exact answer. What I found on page 115 was that in each phospholipid molecule, there is a head which is hydrophilic (loves water) and the tails of the molecule are hydrophobic (hate water). The structure allows them to form boundaries between two watery environments. The membrane is a phospholipid bilayer and what happens is that the hydrophilic heads are facing the water, while the tails are on the other side meeting other tails, and the heads are duplicated on the bottom.
The cell membrane. It's called a bi-layer, and contains two layers of phospholipids. The tails interact with one another while the heads interact with the aqueous solution.
Membranes differ in type but they are all fundamentally made up of phospholipids and work on the principle of self assembly through hydrophobic and hydrophilic interactions with water. A phospholipid is a molecule that has a charged (or polar) head group that includes phosphate ions (hence the phospho.. bit). These head groups are polar in the same way that water molecules are polar, hence the head groups are attracted to water (hydrophilic). The tail of a phospholipid is made up of one or two long hydrocarbon chains which are not polar, and hence repel water and attract to themselves (hydrophobic). So a phospholipid is ambiphilic, ie. simulatenously hydrophobic and hydrophilic. If I were to draw it @ = headgroup I = hydrocarbon chain @ II If you put a large concentration of these molecules in water, the tails will clump together and the polar head groups will point outwards facing the water. A membrane is therefore a double layered sheet of phosholipids that self assemble into double layered membranes: (water) @@@@@@@@@@@@@@@@@@@@ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII @@@@@@@@@@@@@@@@@@@@ (water) these membranes can then have membrane proteins spanning the membrane to act as gateways in and out of the cell. For example KCSA is a potassium ion channel used during nerve signalling.
The bilayer is made up of lipid molecules, in which polar ends are facing outwards (towards cytoplasm in the bottom layer and extracellular environment in the upper layer) and non polar sides are facing each other (hydrophobic interaction). Intrinsic and extrinsic proteins are embedded or attached respectively.
It is a double-layered membrane enclosing the nucleus of a cell that controls what enters and leaves the nucleus. It is also called the nuclear envelope.
It is a double-layered membrane enclosing the nucleus of a cell that controls what enters and leaves the nucleus. It is also called the nuclear envelope.