Which of the following statements are correct? A. Lipid bilayer lacking proteins is highly impermeable to all the charged molecules. B. Channels…
Which of the following statements are correct?A. Lipid bilayer lacking proteins is highly impermeable to all the charged molecules.B. Channels have specific binding pockets for the solute molecules they allow to pass.C. Transporters allow solutes to cross a membrane at much slower rates than do channels.D. The plasma membrane of many animal cells contains open K⁺ channels, yet the K⁺ concentration in the cytosol is much higher than outside the cell.E. The membrane potential of an axon temporarily becomes more negative when an action potential excites it.
Select an option to attempt
Correct Answer: Option A
Explanation
Membrane permeability and ion transport — identifying the INCORRECT statement:Correct statements about biological membranes:A. Lipid bilayer is impermeable to charged molecules (ions, large polar molecules) — TRUEC. Transporters are slower than ion channels (transporters undergo conformational changes; channels are pores) — TRUED. K⁺ remains high inside despite open K⁺ channels because Na⁺/K⁺-ATPase actively pumps K⁺ in — TRUEIncorrect statement (E): 'Action potentials make membrane more NEGATIVE' — FALSE. During an action potential, Na⁺ rushes IN through opened Na⁺ channels, making the membrane potential MORE POSITIVE (depolarisation from −70 mV to ~+40 mV). This INCORRECT statement is the answer.