Question

in which case would facilitated diffusion be needed?A. With large polar molecules moving against the concentrationgradientB. With very small non polar particles moving down theconcentration gradient.C. With very small polar particles moving against theconcentration gradient.D. With large non polar molecules moving down the concentrationgradient.

Answer 1

Biology > Cell biology > Passive transport

There are different types of transport in the cell that can be classified into two groups: passive transport (which does not require energy) and active transport (which requires energy because it goes against the concentration gradient).

Diffusion is a type of passive transport and it does not require energy, it can be divided into simple diffusion (molecules pass through the membrane without the help of any channel) and facilitated diffusion (molecules pass through the membrane with the help of a protein channel).

Facilitated diffusion will transport certain molecules and simple diffusion others. Larger, polar and charged molecules will need help to cross the membrane, so they will do so by facilitated diffusion. Therefore, the answer is D.