Membrane transport proteins make up _____% of all membrane proteins in the cell
15-30%
List some small nonpolar molecules
O2 and CO2
List some small uncharged polar molecules
H2O, glycerol and ethanol
What are some molecules that cannot penetrate the cell membrane by diffusion?
Large uncharged polar molecules, ions and any charged molecules
How do ions and small polar molecules get past the cell membrane?
Through transport proteins that are specific and choosy of what goes through them
What disease causes an inability to transport amino acids like cysteine from urine or intestine into the blood/ Inevitably contributing to kidney stones.
Cystinuria disease
A narrow hydrophilic pore that allows diffusion of specific ions along an electrochemical gradient
Channel proteins
Proteins that bind to the molecule and undergo a conformational change that exposes binding sites for the molecule on different sides of the membrane.
Transporter
T/F An electrochemical gradient is the potential difference in both concentration and electric potential
True
T/F Only channels mediate passive transport
False. Both transporters and channels mediate passive transport
What is Antiport?
The co-transport of ions in opposite direction
What is a symport?
The co-transport of ions in the same direction
What is a uniport?
The transport of a single solute (not coupled)
These pumps are single sub-unit proteins. They phosphorylate themselves and pump ions.
a) P-Type pumps
b) ABC transporters
c) V-Type pumps
d) F-Type pumps
a) P-Type pumps
These pumps are made up of multiple subunits. They pump many different small molecules.
a) P-Type pumps
b) ABC transporters
c) V-type pumps
d) F-Type pumps
b) ABC Transporters (ATP-binding-cassette)
These pumps are made up of multiple subunits. They pump H+ into organelles.
a) P-Type pumps
b) ABC transporters
c) V-type pumps
d) F-Type pumps
V-Type pumps (like in vacuoles)
These pumps use the H+ gradient to synthesize ATP
a) P-Type pumps
b) ABC transporters
c) V-type pumps
d) F-Type pumps
F-Type pumps (work in the reverse of V-Type)
Review Slides
11, 12, 14,
What are the names of the water channels that transport water? Water will quickly and passively move through these types of channels
Aquaporins
_____ channels conduct way better
K+
The Na+-K+ pump produces gradients of high Na+ ______ and high K+ ________ and set up a charge imbalance
Na+ outside and K+ inside
Describe the process of establishing a membrane potential
The Na+-K+ pump pumps Na+ outside the cell and K+ inside the cell. There is a K+ leak channel for K+ to leak outside, making the inside of the cell slightly more negative. Once the (+) and (-) turn the inside neutral that is called the resting membrane potential
When the membrane is polarized (at resting membrane potential), these channels are closed. When the inside is depolarized (less negative inside), they open. What ion channel is this?
Voltage-gated ion channel
This channel is stimulated from mechanical movement or stress
Mechanically gated ion channel
This channel is activated when bound to another molecule. It can be both intracellular or extracellular.
Ligand-gated ion channels
These neurotransmitters open nonselective cation channels allowing an influx of Na+ to depolarize the membrane. Usually taking multiple of these signals to do so.
Excitatory neurotransmitters
These neurotransmitters open the Cl- channels to hyperpolarize the membrane (harder to make the neuron fire)
Inhibitory neurotransmitters
Just know this fact I guess
the stronger the signal, the faster the firing