Membrane Proteins Flashcards
What holds the integral membrane proteins within the phospholipid bilayer?
Regions of hydrophobic R groups that allow strong hydrophobic interactions.
Where are peripheral membrane proteins found?
On the periphery of the membrane. They have hydrophilic R groups and are bound to the membrane by ionic bonds and hydrogen bonds.
What does the phospholipid bilayer act as?
A barrier to ions and most uncharged molecules.
How do carbon dioxide and oxygen pass through the membrane?
By simple diffusion.
What is facilitated diffusion?
The passive transport of substances across the membrane through specific transmembrane proteins.
What allows different cell types to have to perform specialised functions?
Differing channel and transporter proteins.
Why do gated channel proteins change conformation?
To allow or prevent diffusion.
How are ligand-gated channels controlled?
By the binding of signal molecules.
How are voltage gated channels controlled?
By changes in ion concentrations.
What is the function of transporter proteins?
To pass ions and molecules across the membrane.
What is the role of GLUT4?
It is a glucose transporter that provides a route for facilitated diffusion of glucose across the membrane.
What is meant by specialisation?
The differing transporter and transmembrane proteins between different cells. This allows cells to perform different functions by allowing different substances to pas across their membrane.
How do transporter proteins carry ions or molecules across the membrane?
By binding to the specific substance and undergoing a conformational change.
Why do transporters alternate between two conformations?
So the binding site for a solute is sequentially exposed on one side of the bilayer, and then the other.
What does active transport use to transfer substances across the membrane against their concentration gradient?
Pump proteins.
