Question

What is the lipid composition of a normal human cell’s plasma membrane (choose a cell type)? Describe and draw, in detail, the chemical structure of a lipid from your choice.

Answer 1

Now we have Fluid mosaic model as the accepted model for plasma membrane established on 1972.By this model we have the components of membrane are  phospholipids, cholesterol, and proteins

Its structure is as

then about lipid

they are phospholipids. Made of glycerol, two fatty acid tails, and a phosphate.and their head groups are linked. In membrane, bilayer of lipid with their tails pointing in side as shown in figure. They are amphipathic means they are having hydrophilic and hydrophobic parts on same molecule

hydrophilic part is head whih contains phosphate group and -ve charge.this part is facing outside (bilayer) and it is in contact with aqueous fluids

hydrophobic part inside bilayer.long, nonpolar fatty acid tails. The fatty acid tails can easily interact with other nonpolar molecules but they interact poorly with water. Because of this, it’s more energetically favorable for the phospholipids to tuck their fatty acid tails away in the interior of the membrane, where they are shielded from the surrounding water. The phospholipid bilayer formed by these interactions makes a good barrier between the interior and exterior of the cell, because water and other polar or charged substances cannot easily cross the hydrophobic core of the membrane