Test 2 Flashcards
(241 cards)
Which protein in the red blood cell membrane appears to be responsible for the repelling forces that prevent RBCs from sticking to each other?
Glycophorin A
Muscular dystrophy is caused by:
mutations in the dystrophin gene
Membrane proteins are most likely analyzed to determine:
amino acid sequence
When looking for membrane spanning polypeptide sequences, cell biologists look for:
predominantly hydrophobic amino acids that form an α helix
Oligosaccharides are:
chains of fewer than 15 sugars.
What determines the difference between a person with O type blood and AB type blood?
The individual with AB type blood has genes for two enzymes that the person with O type blood does not.
Which of the following lowers the transition temperature of a membrane?
increasing unsaturation of fatty acids and shortening fatty acids.
Cells use desaturase enzymes to increase membrane fluidity in response to:
low temperature
The two leaflets of a cellular membrane:
have different mixes of lipids
Membrane fluidity is important for which of the following activities?
Allowing cell secretion to occur.
Using fluorescence recovery after photo bleaching allowed cell biologist to observe:
the diffusion of membrane proteins back into the bleached area.
Which statement about lipid movement within the phospholipid bilayer is true?
Lipids jump from one compartment to another to move laterally across the cell.
Which of the following involves the transport of a specific molecule across a membrane with the aid of a carrier protein, and additional energy input?
active transport
The diffusion of an electrolyte across a membrane is affected by:
both the concentration gradient and electrochemical gradient
Which statement about membrane permeability is true?
Non polar molecules penetrate faster than polar ones.
A cell shrinks when it is placed into a new solution. The new solution is probably:
hypertonic
The pump that uses ATP energy to concentrate protons into a lysosome is an example of a:
V-pump.
The Na+/K+ ATPase expels out of the cell and pumps into the cell.
Na+/K+.
People who are heterozygous for the CFTR protein may be more likely to survive cholera because:
heterozygous individuals have thicker mucus which may help prevent dehydration
Why can’t Na+ ions pass through the bacterial KcsA K+ channel?
Na+ ions are too small to replace the shell of hydration formed around the oxygen rings.
What part of the bacterial KcsA K+ channel undergoes conformational changes to allow the channel to open and close?
the M2 helices
The inner membrane of an axon goes from -80mV to +40mV during a wave of depolarization. What membrane protein is responsible for this depolarization?
voltage-gated Na+ channels
During saltatory conduction, depolarization occurs:
at the nodes of Ranvier
______ trigger fusion of synaptic vesicles with the synaptic membranes of the pre synaptic cell. These vesicles release ________ into the synapse.
Ca2+ ions, neurotransmitters