Question

The cell membrane is considered polar because it only allows certain compounds to travel through freely. The random movement of molecules down their concentration gradient is called:

Answer 1

Answer:

diffusion

Explanation:

The process of  random movement of ions and molecules  from region of  their higher concentration gradients to the region of lower concentration  gradient is known as diffusion. The kinetic energy  the molecules  process make them to move one direction to another in order to gain free movement

it takes place only in liquid and gaseous medium, and  It is affected by the diffusion distance, but proportional to  the concentration gradient,and the surface area exposed for the diffusion to take place.( based on Fick's Law

In cell membrane because of the composition of the layer,  polar molecules can diffuse freely down  across the membrane  because of their polarities  and small sizes. Water, C02 and oxygen are examples..However some polar molecules are too big to move freely, and therefore need special passages or channels of protein to pass through. e,g glucose, Amino acid.

Answer 2

Answer: It is called diffusion.

Explanation:

Diffusion is the movement of molecules or ion from a region of higher concentration to a region of lower concentration across the cell membrane. Diffusion an either be passive or facilitated in cell membrane. A passive diffusion allows molecules to move from high concentration to low concentration with any assistance across cell membrane, it allow very small or lipid solubles molecule.

Facilitated diffusion is the movement of particles from high to low concentration region area across cell membrane with the help of protein carrier.