Final answer:
Cell membranes do not change their orientation during trafficking between compartments. Cytoskeletal elements maintain micro-discontinuities, preventing the movement of membrane components. Transport between compartments is infrequent and requires extra kinetic energy.
Step-by-step explanation:
Cell membranes do not change their orientation when they traffic between compartments.
Cellular membranes are compartmentalized into microcompartments, and components within these compartments are relatively immobile. Cytoskeletal elements such as actin fibers create and maintain these micro-discontinuities, which prevent the movement of membrane components between compartments. The mechanism of micro-compartmentalization is referred to as the Fences and Pickets model.
Transport between compartments requires extra kinetic energy for molecules to 'jump' across the fences. This type of motion, known as hop diffusion, is different from the random motion implied by the original fluid mosaic model.