Why can saturated fats pack together so tightly while unsaturated fats cannot?

Question

anonymous · Answer

They are linear.

blues · Answer

Lauriy right if not very specific.

Saturated fats contain only single bonds, so rotation about each bond is relatively free. Unsaturated fats contain at least one double bond. The pi electrons prevent free rotation about this bond, so the molecule exists in one of two conformations, cis or trans, depending on whether the hydrogens on the double bonded carbons are on the same (cis) or opposite (trans) sides of the molecule.

This double bond introduces a rigid kink into the hydrocarbon. The saturated fats can group together tightly. Think of a handful of pencils fitting together. The unsaturated fats can't. Think of trying to pack together a handful of broken pencils.