Which type creates a kink (doesn't pack tightly)?

Which type creates a kink (doesn't pack tightly)?

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

Answer: (B)

Cis unsaturated fatty acids have a cis double bond that introduces a bend in the hydrocarbon tail. That bend prevents the tails from aligning neatly, so they can’t pack tightly together. Because the chains don’t stack well, these fats tend to be liquid at room temperature and contribute to membrane fluidity. In contrast, saturated fatty acids and trans unsaturated fatty acids are more linear and can pack tightly, while polyunsaturated fats have multiple bends but still feature cis-induced kinks; the key idea is that the cis configuration creates the kink that disrupts tight packing.

Cis unsaturated fatty acids have a cis double bond that introduces a bend in the hydrocarbon tail. That bend prevents the tails from aligning neatly, so they can’t pack tightly together. Because the chains don’t stack well, these fats tend to be liquid at room temperature and contribute to membrane fluidity. In contrast, saturated fatty acids and trans unsaturated fatty acids are more linear and can pack tightly, while polyunsaturated fats have multiple bends but still feature cis-induced kinks; the key idea is that the cis configuration creates the kink that disrupts tight packing.