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
If two molecules A & B move in the same direction. This movement can be called
Antiport
Symport
Uniport
Guttation
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
Which of the following is not correct regarding carrier molecules, involved in facilitated diffusion?
It helps in transporting molecules down the concentration gradient.
It is specific.
It is saturable.
It requires energy input.
Facilitated diffusion involves?
Downhill transport
Without expenditure of energy
Involvement of proteins
All
If two molecules A & B move in the same direction. This movement can be called
Antiport
Symport
Uniport
Guttation
Consider the following statements and choose the correct answer
I. Carrier proteins are needed by both facilitated diffusion and active transport and are sensitive to inhibitors that react with protein side chain
II. Different types of proteins present in the membrane plays a major role in both active as well as passive transport
III. The carrier proteins needed by facilitated and active transport are specific
IV. There is no need of energy to pump molecule against a concentration in active transport
V. Transport rate reaches to saturation point, when all the active proteins are used
I, II, II, IV and V
I, II and III
V, IV and I
I, II, III and V
Which characteristic distinguishes facilitated diffusion from simple diffusion across a biological membrane?
Movement down a concentration gradient
Specificity for the transported molecule
Passive transport requiring no energy input
Dependence on membrane fluidity
Facilitated diffusion
Needs a carrier protein
Is an active process
Occurs against the concentration gradient
Needs ATP
Read the following statements regarding porins and select the correct option given below
I. Porins are transport proteins
II. Channel proteins are a type of transport protein, which are usually gated
III. Carrier protein binds the particular solute to be transported
IV. Particular solute is delivered to the other side of the membrane by carrier proteins
I, II and III
I, III and IV
I, II, III and IV
I and IV
Which of the following statements regarding facilitated diffusion is INCORRECT?
It requires transport proteins.
It is a passive process and does not require energy.
It can move molecules against their concentration gradient.
Transport proteins involved can become saturated.
