Explain6 marksChallenge
A researcher investigates the effect of cholesterol on membrane fluidity using artificial phospholipid bilayers. Two types of liposomes are prepared: Type A (phospholipids only) and Type B (phospholipids with 30% cholesterol by mass). Membrane fluidity is measured at 15°C and 40°C using fluorescence recovery after photobleaching (FRAP); a higher recovery rate indicates greater fluidity. The results are shown below.
| Temperature | Type A (no cholesterol) | Type B (with cholesterol) |
|---|---|---|
| 15°C | 0.3 | 0.6 |
| 40°C | 0.8 | 0.5 |
Explain how cholesterol contributes to the observed differences in membrane fluidity at the two temperatures. In your answer, also describe the roles of other components of the cell surface membrane (glycolipids, glycoproteins, and carrier/channel proteins) in maintaining membrane stability and function.