This needs to be very detailed so I can get a full understanding of it. Thank you© BrainMass Inc. brainmass.com October 9, 2019, 4:16 pm ad1c9bdddf
Every molecule will move on its own from an area of high concentration to an area of low concentration. This process occurs naturally and requires no external source of energy. It is a spontaneous process meaning that the change in free energy for this process is negative. When molecules move from high to low concentration, eventually, if nothing else happened, there would no longer be any concentration gradients left. Equilibrium would be reached and we would all be dead. The process of random movement toward a state of equilibrium is called diffusion. Diffusion works when molecules move from an area of high concentration to an area of low concentration. The speed at which diffusion occurs is based, in part, on the concentration gradient, the difference in concentration between the high area and the low area. In cells, diffusion can be a problem even though the distance to be traveled from high to low may be very short. The barrier to simple diffusion is the plasma membrane. Some molecules can cross the membrane directly, such as small, uncharged molecules like ethanol, and even larger ...
This solution is comprised of a detailed summary on the various methods of membrane transport. This summary is organized so that it first discusses the processes which do not require any external energy sources and then goes on to discuss methods which do require energy, more generally known as active transport. Since the methods which require external energy vary in the form of energy required, an in-depth explanation of the types of active transport is provided.