Effects of Fatty Acid Saturation on Membrane Fluidity

In biological systems, lipids are a diverse group of molecules that play crucial roles in maintaining cell structure and function. One major class of lipids, phospholipids, is essential for forming cell membranes. These amphipathic molecules contain both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, which allow them to arrange themselves into bilayers. This bilayer structure is fundamental to cellular integrity and function.

The properties of lipids are closely associated with their molecular structure. For example, the saturation of fatty acids in phospholipids impacts membrane fluidity. Unsaturated fatty acids have one or more double bonds that create kinks in the fatty acid tails, preventing tight packing. In contrast, saturated fatty acids have no double bonds and can pack closely together. Understanding these differences is key when considering how membrane fluidity affects various biological processes.

Given this information, which of the following statements best describes the relationship between fatty acid saturation and membrane properties?