Membrane Fatty Acid Explorer

Membrane Fluidity: One of Many Cold-Water Adaptations

Fish have evolved numerous adaptations to thrive in freezing waters. Here we explore one important adaptation found in some cold-water fish species:

• Unsaturated fatty acids contain double bonds that create kinks in the carbon chains
• These kinks make them more difficult to compact, keeping membranes fluid
• The more unsaturated a lipid is, the more liquid it remains at low temperatures
• Fish increase unsaturated fatty acid content in winter through dietary changes
• This allows membranes to stay fluid even in near-freezing water

Use the temperature slider to observe how membrane fluidity changes with temperature. Notice how the phospholipid tails become more rigid at higher temperatures!