Problems
Problem : Why is it necessary
for cell membranes to have proteins that help transport molecules?
The cell membrane is composed of a lipid
bilayer that is highly impermeable to most molecules. As a result, outside
structures are required to help transport essential large, polar molecules
across the cell membrane.
Problem : What is the name of
the natural process by which molecules flow from an area of higher
concentration to one of lower concentration?
Diffusion.
Problem : What is the difference
between the behavior of carrier and channel proteins?
Carrier proteins allow specific molecules to
cross the cell membrane by undergoing a conformational change upon the binding
of the molecule. The conformational change opens a hole through which the
molecule can enter or exit a cell. Channel proteins do not require the binding
of a molecule and conformational change to open. Channel proteins allow
molecules to steadily diffuse across the membrane through diffusion.
Problem : What is the function
of an ionophore?
Ionophores function to increase a membrane's
permeability to a specific ion thereby facilitating its movement across that
cell's membrane.
Problem : Name two specific
functions of membrane transport.
Membrane transport helps maintain the proper
distribution of ions across a cell membrane; helps maintain proper cellular pH,
and helps mediate communication between cells in multi-cellular organisms.
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