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27 Cards in this Set
- Front
- Back
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list the three types of protein pathways through the membrane
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pores
channels carrier |
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list whether the protein pathway through the membrane is open or closed or mixed.
pores channels carrier |
pore -> always open
channel -> alternately open and closed carrier -> equipped with at least two gates that are NEVER open at the same time |
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large-size pores are called?
where are they found? |
Porins
outer membranes of gram-negative bacteria and mitochondria |
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a type of porin that allows water
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aquaporin
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name the two types of transport in Carriers
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Primary active transport
Secondary active transport |
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of the three types of protein pathways through the membrane, list them in descending order from fastest to slowest
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pores
channels carriers |
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One or more solutes that are moved against an electrochemical potential gradient. Requires ATP directly for energy.
Name three examples of that type of transport |
Primary Active Transport
Na/K pump Ca pump H-K pump |
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the NKA pumps out ? sodium ions from the ICF to the ECF and ? potassium ions from the ECF to ICF
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3 sodium ions out of the cell
2 potassium ions into the cell |
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describe the NKA pump structure
which has the ATPase activity? the binding sites for the transported ions? |
α and β subunits
α subunit α subunit |
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what are the two confomational states of NKA?
which faces the ICF? affinity for? which faces the ECF? affinity for? |
E1 and E2 states
E1 state - sodium E2 state - potassium |
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class of drugs that inhibit NKA pumps
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cardiac glycosides
-ouabain -digitalis (digoxin) |
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cardiac glycosides bind to where in NKA pumps?
what does it do? what will happen to the cell's level of ions? |
E2 STATE ---near the K+ binding site on the ECF
prevents conversion of E2 to E1 [Na+] increase [K+] decrease |
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cardiac glycosides can effect NKA pumps and also ? pumps
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NCX
(Na+ - Ca2+ exchanger) |
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a pump that extrudes Ca2+ from the cell.
exchange rate? |
Plasma Membrane Ca2+ - ATPase
(PMCA) 1 H+ -> into cell 1 Ca2+ -> out of cell 1 ATP ->energy |
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where besides the plasma membrane do Ca2+ pumps exist?
what are their roles? |
Sarcoplasmic Reticulum (SR) in muscle cells
Endoplasmic Reticulum in other cells sequesteration of Ca2+ into intracellular storage |
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Name the type of Ca2+ pump that is found inside the cell
what is the rate? |
Sarcoplasmic and Endoplasmic Reticulum Calcium ATPase
(SERCA) 2 H+ ---> out of storage 2 Ca2+ ---> into storage 1 ATP |
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Name the two conformational states of SERCA and PMCA
which has a high affinity for calcium? facing which direction? |
E1 and E2 states
E1 state facing ICF (for both PMCA and SERCA) PMCA pumps it out of cell SERCA pumps it into the lumen of SR or ER |
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what type of pumps would you typically find in parietal cells of the gastric gland? (also in kidney and intestines)
pump rate? |
H+ - K+ ATPase
(HKA) 2 H+ out of cell (into lumen) 2 K+ into the cell 1 ATP |
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What is the HKA pump composed up of?
which subunit is phosphorylated during its catalytic cycle? |
α and β subunits
α subunit |
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Type of transport that moves two or more solutes in a coupled manner
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Secondary Active Transport
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name the two types of Secondary Active Transport
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Co-transport aka SYMPORT
Counter-Transport aka ANTIPORT |
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what is Co-Transport?
(synport) |
a UPHILL solute moves in the SAME direction of a solute that is moving DOWN its gradient
(basically both going same direction) |
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what is a Counter-Transport?
(antiport) |
UPHILL solute moves in the OPPOSITE direction of a solute that is moving DOWN its gradient
(basically one is going the opposite way of the other) |
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Name examples of Cotransporters
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Na+ Glucose Cotransport (SGLT)
Na+ Amino Acid Contransport Na+ - K+ - 2Cl- Cotransport (NKCC) |
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where would you find a Na+/Glucose cotransporter (SGLT)?
rate? |
APICAL MEMBRANE of the cell that lines the proximal tubule and small intestine
2 Na+ into the cell 1 glucose into the cell |
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Describe Na/K/Cl cotransporter (NKCC)
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Na+ going in (with gradient)
Cl- and K+ going out of cell |
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the ? pump and the ? exchanger keep intracellular [Ca2+] four orders of magnitude ? than extracellular [Ca2+]
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Ca2+
Na-Ca LOWER |
