Explain why the flexibility of a membrane increases when more of the phospholipids in the layers contain double bonds

When these bonds have more bends in them (as they will with double bonds), they cannot pack themselves as tightly together. This more-loosely arranged lipid bilayer will allow for a greater degree of flexibility than will membranes that have tightly-packed lipids.

Molecules called lipids have long hydrocarbon chains that determine the way they act. they can be fats, oils, or hormones, and even exist in our cell membranes