Transport occurs along the concentration gradient.

Select the incorrect statement with respect to facilitated diffusion.

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 chains.
$II.$ Different types of proteins present in the membrane play 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 molecules against a concentration gradient in active transport.
$V.$ Transport rate reaches a saturation point when all the active proteins are used.

$A$ plant with well-washed roots was placed in a beaker of water diluted with red ink. The red colour travelled up the stem and into the leaf veins. Which of the following is the explanation for the uptake of red ink into the roots?

Water channels are

Which of the following does not require carrier molecules during transport through cell membranes?