Question

What is diffusion and type of diffusion?​

Answer 1

${\textbf{\underline{Diffusion\: Definition}}}$⤵⤵⤵
$<font color="red"><b>$Diffusion is a physical process that refers to the net movement of molecules from a region of high concentration to one of lower concentration. The material that diffuses could be a solid, liquid or gas. Similarly, the medium in which diffusion occurs could also be in one of the three physical states.

$\boxed{\fcolorbox{blue}{aqua}{Types of Diffusion}}$

Diffusion can either be simple diffusion and be facilitated by another molecule
$\huge\boxed{\fcolorbox{blue}{aqua}{Simple Diffusion}}$

Simple diffusion is merely the movement of molecules along their concentration gradient without the direct involvement of any other molecules. It can involve either the spreading of a material through a medium or the transport of a particle across a membrane. All the examples given above were instances of simple diffusion.
$\boxed{\fcolorbox{blue}{aqua}{facilitated diffusion}}$

On the other hand, facilitated diffusion, as the term indicates, requires the presence of another molecule (the facilitator) in order for diffusion to occur. Facilitated diffusion is necessary for the movement of large or polar molecules across the hydrophobic lipid bilayer. Facilitated diffusion is necessary for the biochemical processes of every cell since there is communication between various subcellular organelles. As an example, while gases and small molecules like methane or water can diffuse freely across a plasma membrane, larger charged molecules like carbohydrates or nucleic acids need the help of transmembrane proteins forming pores or channels.

Answer 2

Diffusion is the process in which net movements of molecule from a region of higher concentrations to lower concentrations .