Membrane Dynamics And Membrane Transport Flashcards
What are peripheral membrane protiens
They’re attached to the membrane by weak non covalent bonds (ionic, h bonding)
Normally outside lipid membrane and sometime part of some protein complexes have integral membrane proteins that are attached internally
They’re dynamic (can be released/recruited to by the membrane due to weak interactions)
Mostly hydrophillic
What is the role of peripheral membrane protiens
Signal transduction
Mechanical support for the membranes
Anchor for integral membrane protiens
Enzymes
How to red blood cell peripheral membrane protiens work
The cell has a network of protiens that give it its concave shape by interactive with the integral membrane protiens
Spectrin is the protien complex that does this, it’s on the internal side of the membrane
What are lipid anchored protiens
Proteins outside the bilayer on either extracellular or cytoplasmic side
Covalently linked to lipid molecules in the bilayer
What are GPI - anchored protiens
A type of lipid anchored protien that’s attached to the membrane by a small complex oligosaccharide thats linked to PI in the membrane
Is faces the extracellular space and played roles in cell adhesion and receptors
What are hydrocarbon chains embedded in the lipid bilayer
A type of lipid anchored chain that’s attached to the cytoplasmic leaflet of the membrane
Plays roles in signal transduction
What type of movement is easily done by phospholipids
What type is more restricted
Moving laterally across one membrane leaflet is easy
Flip flopping to other leaflet (transverse diffusion) is harder
What enzymes helps in lipids movement and establishes membrane assymetry
Flippase
What special about cholesterol when talking about lipid movement
If has a small polar (OH) head group so it can easily flip flop across leaflets
What is passive transport and what ways can it happen
Doesn’t require atp, occurs by diffusion (high to low solute concentration
Can occur through just membrane, a channel, or a facilitative transporter
What is active transport and what ways can it happen
Requires energy (ATP)
Can move diff again concentration gradient (low to high)
Happens through use of pumps
What types of thing can do simple diffusion just through lipid bilayer
What things can’t
Small inorganic solutes : O2, CO2, H2O
Solutes with high lipid solubility (ex. Caffine)
Can’t : ions and polar organic solutes (sugar/amino acids)
Anything too big
What is osmosis and what give hyper hypo and iso tonic solution
Water move through the membrane from region of low solute to high solute
Hyper if more solute on outside of cell
Hypos if less solute on outside of cell
ISO if equal on inside and outside
What are aquaporin
Channel protiens for simple diffusion the help better water diffusion
Lets the cells be more permeable to water
What are ion channels
For simple diffusion, Transmembrane structure that is HIGHLY selectively permeable to specific ions (NA K CA CL)
Most are gated: meaning they change confirmation to be open or closed
