Question

which part of a phospholipid molecule makes up most of the thickness of a cell surface membrane​

Answer 1

Answer:

All of the lipid molecules in cell membranes are amphipathic (or amphiphilic)—that is, they have a hydrophilic (“water-loving”) or polar end and a hydrophobic (“water-fearing”) or nonpolar end. The most abundant membrane lipids are the phospholipids. These have a polar head group and two hydrophobic hydrocarbon tails.

Explanation:

Answer 2

The lipid molecules present in cell membranes are amphipathic that's why they have hydrophilic or hydrophobic end. The phospholopids are the most abundant lipid layer. It contain a polar head group and two hydrophobic hydrocarbon tails. Glycerophospholipids are the most abundant lipids present in cell membranes.