Final answer:
Membrane fluidity is influenced by the proportion of unsaturated fatty acids, the length of fatty acid chains, and the proportion of cholesterol in the bilayer. However, the ratio of glycolipids to phospholipids does not directly affect membrane fluidity.
Step-by-step explanation:
The fluidity of a cellular membrane is influenced by several factors, which include the composition of the fatty acids in the membrane lipids and the presence of other molecules such as cholesterol. The proportion of unsaturated fatty acids in the lipids affects membrane fluidity because unsaturated fatty acid tails contain one or more double bonds that introduce kinks, preventing the tails from packing tightly together. This increases the fluidity of the membrane. The length of the fatty acid chains also has an impact; shorter chains reduce the tendency of the lipids to interact strongly with one another, also increasing fluidity. The proportion of cholesterol in the bilayer influences fluidity as well. Cholesterol acts as a fluidity buffer, with different effects depending on temperature; at high temperatures, it stabilizes the membrane, making it less fluid, whereas at low temperatures, it prevents the membrane from solidifying, thereby maintaining fluidity.
However, the ratio of glycolipids to phospholipids does not directly influence the membrane's fluidity. While glycolipids play a role in cell recognition and signal transduction, they do not alter the physical properties that determine fluidity in the same way that unsaturation, chain length, or cholesterol content does.