Which configuration causes kinks that prevent tight packing?

Which configuration causes kinks that prevent tight packing?

• A. Trans unsaturated fatty acids
• B. Mono-unsaturated
• C. Cis unsaturated fatty acids
• D. Saturated fatty acids

Answer: (C)

Kinks come from the cis arrangement of a double bond in fatty acids. In cis unsaturated fatty acids, the hydrogens on the double-bond carbons are on the same side, which bends the tail and creates a kink. That bend prevents the tails from stacking tightly together, so they don’t pack tightly and membranes stay more fluid. Trans unsaturated fats have a straighter shape (the hydrogens are on opposite sides), so they can pack more tightly, similar to saturated fats, which have no kinks and pack even more tightly. Mono-unsaturated can include cis or trans, but the specific cause of the bend that prevents tight packing is the cis configuration.

Kinks come from the cis arrangement of a double bond in fatty acids. In cis unsaturated fatty acids, the hydrogens on the double-bond carbons are on the same side, which bends the tail and creates a kink. That bend prevents the tails from stacking tightly together, so they don’t pack tightly and membranes stay more fluid. Trans unsaturated fats have a straighter shape (the hydrogens are on opposite sides), so they can pack more tightly, similar to saturated fats, which have no kinks and pack even more tightly. Mono-unsaturated can include cis or trans, but the specific cause of the bend that prevents tight packing is the cis configuration.