What portion of the molecule in model 1 is responsible for the "-lipid" part of the name?

The portion of the molecule that is responsible for the lipid part of the name is THE LIPID TAILS.
A typical phospholipid molecule is made up of two distinct regions which are the head and the tail regions.
The head region is made up of the phosphate group and is polar in nature. The tail region is made up of the fatty acid components and is non polar in nature. Thus, the head of the phospholipid is hydrophilic while the tail region is hydrophobic.

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