Membrane Structure Flashcards
Membranes act as […]
Membranes act as selective barriers
What is responsible for blocking the passage of most water-soluble molecules from entering the cell?
The lipid bilayers block the passage of most water-soluble molecules
The plasma membrane is more than a barrier, it is the […] the cell has with its environment
The plasma membrane is more than a barrier, it is the interface the cell has with its environment
Membranes are composed of […] and […]
Membranes are composed of lipids and proteins
Membrane lipids are […]
Membrane lipids are amphipathic and have two distinct regions a hydrophilic head and hydrophobic tails
The most abundant lipids in membranes are […]
The most abundant lipids in membranes are phospholipids
Different phoshpolipids have different […]
Different phoshpolipids have different head groups
Most lipids are either […] or have a […]
Most lipids are either net neutral or have a net negative charge
Most membranes in cells have a […]
Most membranes in cells have a net negative charge
Membranes also contain […] and […]
Membranes also contain cholesterol and glycolipids
Membrane lipids from […] in water
Membrane lipids from bilayers in water
Phospholipid bilayers spontaneously close to form […]
Phospholipid bilayers spontaneously close to form sealed compartments
What does the fluidity of a mebrane refer to?
Fluidity of a membrane refers to the lateral movement of lipids and membrane proteins
Membranes with […] hydrocarbon chains are
less fluid than ones containing […]lipids
Membranes with saturated hydrocarbon chains are less fluid than ones containing unsaturated lipids
[…] alters membrane fluidity
Cholesterol alters membrane fluidity
The plasma membrane lipid bilayer is […] and is largely due to the activitiy of enzymes called flippases
The plasma membrane lipid bilayer is asymmetric and is largely due to the activitiy of enzymes called flippases
What are the functions of plasma membrane proteins?
- Transporters
- Anchors
- Receptors
- Enzymes
Each memrbane protein has a specific […] with respect to the lipid bilayer
Each memrbane protein has a specific orientation with respect to the lipid bilayer
Polypeptides often cross membrane bilayers as an […]
Polypeptides often cross membrane bilayers as an alpha-helix
Allpha-helix enables […] to interact with each other favorably (via H-bonds), rather than unfavorbly with the hydrophobic lipid tails
Allpha-helix enables polar mainchain atoms to interact with each other favorably (via H-bonds), rather than unfavorbly with the hydrophobic lipid tails
A […] can be formed by multiple transmembrane alpha helices
A hydrophilic pore can be formed by multiple transmembrane alpha helices
How can one measure protein diffusion within membranes?
FRAP experiments assess mobility within membranes
How can the lateral mobility of plasma membranes be restricted?
- Bindings to proteins of the cell cortex
- Binding to the extracellular matrix
- Binding to proteins of the surface of another cell
- Diffusion barrier (dense network of proteins)
A […] forms the cell cortex in red blood cells
A spectrin meshwork forms the cell cortex in red blood cells
