Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Diffusion is an example of passive transport
...


These proteins form water-filled hydrophilic channels across the membrane
...
The channels are selective, each opening
in the presence of a specific ion
...


Diffusion is defined as: The net movement of molecules or ions from a
region where they are more highly concentrated to one where their concentration is lower until evenly distributed
...
The ions bind with the protein causing
it to change shape in a way that closes it to one side on the membrane and opens it to
the other side
...


Carrier Proteins:
An alternative form of facilitated diffusion
...
This causes it to change
shape in such a way that the molecule is released to the inside of the membrane
...
The molecules move from a region where they are highly
concentrated to one of a lower concentration, using only the kinetic energy of the
molecules themselves
...
Charged ions and polar molecules do not diffuse easily
...
This process is facilitated diffusion
...
Like diffusion, it occurs down a concentration gradient,
but it differs in that it occurs at specific points on the plasma membrane where
there are special protein molecules (protein channels/carrier proteins)

---