Final answer:
The relative rate of diffusion of plasma-membrane proteins versus lipid-anchored proteins is gauged using methods like FRAP or SPT. A larger surface area increases the rate of diffusion, while thicker membranes slow it down. Lipid-anchored proteins often diffuse faster due to their solubility in the membrane's hydrophobic environment.
Step-by-step explanation:
Researchers can determine the relative rate of diffusion of plasma-membrane proteins versus lipid-anchored proteins using various experimental techniques such as fluorescence recovery after photobleaching (FRAP) or single-particle tracking (SPT). In general, these methods allow researchers to measure how quickly molecules move within the plane of the membrane. The rate of diffusion is influenced by many factors, including but not limited to membrane solubility, protein size, and interactions with other cellular components.
In terms of plasma membrane thickness and surface area, a larger surface area facilitates a higher rate of diffusion, while an increase in membrane thickness generally slows down diffusion. Lipid-soluble or nonpolar substances pass through membranes more readily than polar substances, which is why lipid-anchored proteins typically diffuse faster than many plasma-membrane proteins that may require the assistance of transport proteins or channels to navigate through the more hydrophobic membrane environment.
Relative rates of diffusion can vary significantly based on the characteristics of the molecules involved. In the case of plasma-membrane proteins, facilitated diffusion might be necessary to overcome barriers posed by the hydrophobic interior of the membrane. Contrastingly, lipid-anchored proteins, being more compatible with the membrane's hydrophobic nature, can often diffuse more readily without such assistance.