â¢ Kidney Disorders: Hematuria may also be caused by damage to the upper urinary tract or an infected kidney. â¢ Bladder and Kidney Cancer: The presence of blood in the urine might also indicate bladder cancer or kidney cancer. However, this is a more common concern in people older than 40 years of age.
Facilitated Diffusion. Facilitated Diffusion is another form of passive transport where many polar molecules diffuse with the help of integral proteins in the lipid bilayer. The two main types of this kind of transport are ion channels and gated channels.
Since the movement of substances is by passive transport, this process does not require chemical energy (in contrast to active transport). In moving substances across a biological membrane, a passive transport may or may not need the assistance of a membrane protein. There are four major types of passive transport: