<prompt> Rate limiting step in facilitated diffusion?Availability of contranspoConformational change in transpoerSynthesis of carrier proteinPolarization of solute  <response>: Ans. isbi.e., Conformational change in transpoerRef: Essentials of membrane Biophysics p. 25I.The relative slowness of the rate constant for conformational change reorienting the Solute-unoccupied transpoer Step-4 makes it the rate-limiting step in the process of facilitated diffusion. 