which of the following lipids are distinctly enriched in lipid rafts?
cholesterol or sphingloplipds
which of the following statements about the relative concentrations of Na+ and K+ inside and outside of a typical mammalian cell is true?
the concentration of Na+ outside the cell is 30 times higher then inside cell, and the concentration K+ inside the cells is 10 to 30 times higher then outside the cell
which of the following statements about ABC transporters is false?
each member of the family Cl- channel
although Na+ is smaller than K+, its passage through the K+ channel is blocked by ________ filter
selectivity
two examples of membrane lipids that are present in small amounts are
glycolipids and phosphatidylinositol
active transport differs from facilitated diffusion in that
active transport involves the transport of molecules up their concentration gradient
which of the following statements about ion channels is true?
they are opened either by the binding of ligands or by the changes in electric potential across the membrane
the ingestion of large particles by cells is a form of endocytosis called
phagocytosis
what is the primary reason red blood cells from mammals are used to study the plasma membrane?
they lack nuclei and membrane bound organelles
which of the following is not involved in receptor mediator endocytosis?
pseudopodia
all of the following are involved in receptor mediated endocytosis
adaptor proteins
clathrin
internalization signals
membrane proteins are able to move
laterally within the plane of the membrane
mutations in the internalization single of endocytoic receptors prevent their interaction
adaptor proteins
the resting plasma membrane potential as described by the Nernst equation is the sum of the movement of ions. However, in practice, the movement of a single ________ ion, is the major component in determining the membrane potential
K+
which of the following are integral membrane proteins that do not contain a transmembrane alpha helix?
GPI anchored proteins
LDL uptake by cells is one of the functions of
receptor mediated endocytosis
the pH of endosomes and lysosomes is
acidic
which of the following statements about the glucose transporter is false?
flow through it unidirectional
which of the following will not solubilize in a typical peripheral membrane protein
middle hypertonic saline
all of these will solubilize a typical peripheral membrane protein
extreme pH
high salt concentration
detergent
facts about the glucose transporter
-it transports glucose across the plasma membrane via a mechanism called "facilitated diffusion
-it has 12 alpha helical transmembrane segments
-a conformational change in the transporter is involved in the transport process
a feature common to most transmembrane proteins is
an alpha helical region of about 20 to 25 hydrophobic amino acids
transport of glucose into the intestinal epithelium is driven by ion gradients established by the
Na+-K+ pump