Membrane Fluidity

Notes

How to control membrane fluidity: 

1. Saturation 

If the fatty acid tails are saturated, they will be densely packed together. Remember, if something is unsaturated, it means it contains double bonds which “kink” the linearity of the molecule. 

Increased saturation results in a higher melting temperature since they are densely packed. 

2. Chain length

If it is longer, it will be more rigid. If it is shorter it will be more fluid. 

3. Cholesterol: this is ambiguous and acts as a fluidity buffer! 

In high temperatures→ it stops phospholipids from moving around, meaning it decreases fluidity.

In low temperatures→ it stops membranes from becoming too rigid, meaning it increases fluidity! 

*Remember, hopanoids are bacterias version of cholesterol, and sterols are for plants!