Lecture 15 Membrane Structure (ch11) Flashcards
What is more abundant, proteins or lipids in the cell membrane? (and by how much)
Lipids are 50x more than proteins
What makes up 50% of the membrane mass and does most of the cell membrane’s functions?
Protiens! Because they are bigger they take up more mass
What is an example of an anchor protein?
Integrin
What is an example of an ion channel proteiN?
K + leak channel (K+ can leave cell)
Which portion of the membrane associated proteins are hydrophobic?
The part that is inside the membrane.
Which portion of the membrane associated proteins are hydrophillic?
The part that is in the cytosol or outside the cell (interstitial space)
What type of protein is peripheral?
Protein attached protein (1 protein attached to another)
Which protein is integral but not in the membrane?
Lipid linked protein
What conformation is a protein that crosses the cell membrane (most cases)? What is this protein called?
Alpha helical; transmembrane protein
A multipass transmembrane protein with multiple alpha helices is oriented how? If this is the case it is called a ____ ___
Each of the pieces face their hydrophobic side in and hydrophilic side out; a nuclear pore
If there is a multipass transmembrane protein with beta sheets, what does it form? What is an example?
A beta barrel; porin proteins
What do porin proteins form?
Channels holding water in the outer membrane of bacteria
How can we take out a protein forma membrane to study its function? What is the con?
Detergent; Can disrupt the protein structure :(
What is an alternative to detergent?
Cryonelectromicroscopy- study proteins while still IN membrane
What are two commonly used detergents?
SDS and triton X100
What do detergents from?
Micells (little balls that look like dandelions)
What is the main component of the RBC cortex? Mutations of this would cause ___
Spectrin; anemia
How is spectrin attached to the RBC membrane?
Actin moves transmembrane proteins to connect spectrin — membrane
What side foes the protein cortex attach to of the membrane? WHat is its job?
Protein cortex —cytosol side of membrane; biconcave disc shape
Other than RBCs, other human and animal cells have a cortex composed of ____ and ___
actin and myosin
What organisms have a cell wall instead of a cortex?
Plants, yeasts, and bacteria
What did the mouse -human hybrid cell experiment tell us?
Proteins can move laterally in each single layer of the bilayer (most proteins)
What is it called when a membrane protein is ‘grounded’ to its spot?
A membrane domain
Give examples of how a cell can be restricted movement by tethering?
To the cortex, the extracell matrix, to to other proteins of another cell’s surface
