A researcher is studying facilitated diffusion of a novel solute 'X' across a cell membrane using an artificial lipid bilayer system. They observe that increasing the concentration of X on one side of the membrane increases the rate of transport, but only up to a certain point. Beyond this point, further increases in X concentration do not affect the transport rate. Which of the following BEST explains this observation?
The membrane has reached its maximum permeability for X.
The solute X is being actively transported at higher concentrations.
Saturation of the carrier proteins
The solute X is inhibiting its own transport through feedback regulation.
Related Questions
    Water channels are possessed by a membrane to facilitate the movement of hydrophilic substances.
These channels are made up of
Proteins
Lipids
Carbohydrates
Nucleic acids
    What is mandatory in the process of facilitated diffusion?
    Presence of concentration gradient
A carrier protein
A hydrophilic moeity
All of the above
