what is the movement in simple diffusion?

Question

you know.... like how do the molecules move in the concentration. Is it random, controlled, or in a certain direction.

Answer 1

Diffusion
Diffusion is the net movement of particles from an area of high concentration to an area of low concentration. For example, diffusing molecules will move randomly between areas of high and low concentration but because there are more molecules in the high concentration region, more molecules will leave the high concentration region than the low concentration one. Therefore, there will be a net movement of molecules from high to low concentration. Initially, a concentration gradient—a smooth decrease in concentration from high to low—will form between the two regions. As time progresses, the gradient will grow increasingly shallow until the concentrations are equalized.

Answer 2

Molecules move because of Brownian motion, in a random direction (and the speed is directly related to their temperature). When things diffuse they generally move from a region with a high concentration to one with low. How can both statements be true? The direction of movement is random, but in the area with more molecules, there would be more collisions between molecules, which would tend to propel them away from the area of high concentration...

Answer 3

simple diffusion means diffusion is diffusion toward equilbrium or where the sum of the net force will equal zero, if it is a uncharged species then it would simply be goverened by theconcentration gradient, if it is a charged species (like ions) it will be governed by both the electrochemical and concentration gradient, so it is possible to have simple diffusion of molecules agaisnt their concentration gradient if the electrical driving force is opposite and greater than the concentration gradient, and this happens in biology all the time (action potentials)

Answer 4

From a higher concentration to a lower concentration. Like if the is a whole bunch of salt outside the cell and very little inside the cell; salt moves into the cell until both side are equal. or something like that.