Exam 3 Transport through Membranes I ACTIVE Flashcards
small and hydrophobic; how likely to cross lipid bilayer without any help?
easy to get across lipid bilayer
small and polar; how likely to cross lipid bilayer without any help?
might get across lipid bilayer
large and polar; how likely to cross lipid bilayer without any help?
will not cross lipid bilayer
charged/ion; how likely to cross lipid bilayer without any help?
will not without help
no energy required and solute travels from high to low concentration describes what type of transport?
passive
main form of energy is ATP hydrolysis and we are either creating a concentration gradient or reinforcing it; describes what type of transport?
active
what are the 3 general modes of transport
- uniporter = moves 1 thing with no specificity on direction
- symporter = same; movement of 2 things in same direction
- antiporter = opposite; movement of 2 things in opposite direction
what are the 3 general categories of transporters?
- pumps = perform active transport; fights the concentration gradient
- carriers = coupled to primary transport pump; 2ndary transport carriers
- channels = passive transport
what are the 2 types of primary active transport pumps?
- p-type pump
2. ABC transporter
what are the 4 pieces to a p-type pump to identify that is what being used in transport?
- transmembrane domain spans the lipid bilayer
- A/Actuator (hinge) links cytosolic domains to transmembrane domain
- N/Nucleotide binding domain binds ATP
- P/Phosphorylation domain accepts the phosphate from ATP
E1 is open to _ side
cytosolic side; binds molecule
E2 is open to _ side
“outside”; releases molecule and may/may not bind another type molecule
Ca++ transport uses what mode and pump for transport?
uniporter a P-type
what are the names for Ca++ transport pumps?
SERCA (muscle cells)
PMCA (plasma membrane)
SPCA (Golgi secretion pathway)
Na+/K+ pump uses what mode and pump for transport?
antiporter a P-type
Flippases uses what type of transport
p-type
what is the goal of flippases?
to perform a transverse (flipping) motion within plasma membrane as to internalize lipids on exterior cell membrane or recycle endosomes on Golgi
what is a common molecule to be internalized via flippase?
phosophatidylserine (PS)
what is the general mechanism for p-type pumps?
capture (E1) -> ATP (self) -> eversion (E2) -> release -> bind something else (E2)
in plants and fungi, Na+/K+ pump is replaced by
H+-ATPase
what pump maintains the pH of the stomach lumen?
H+/K+-ATPase
what pump maintains proper levels of trace metals?
Heavy Metal ATPases
what are the 3 pieces to a ABC pump to identify that is what being used in transport?
- Duplicates*
1. 2 transmembrane domains
2. 2 Nucleotide biding domains for ATP
3. importers require a substrate binding protein
what is the goal of an ABC transporter?
to phosphorylate something else
general mechanism of ABC transporter?
bind molecule (not ions!) -> ATP and dimerize -> eversion -> release molecule
MDR proteins use what type of pump?
ABC; exporter used for drug resistance (incr MDR proteins = incr resistance)
CTFR use what type of pump?
ABC; Cl- exporter
what makes CTFR a noncanonical ABC transporter?
ATP hydrolysis is inefficient so acts live a passive/ligand-gated channel
CTFR altered ion movement results in:
increased osmotic pressure which thus allows for secreted mucins to interact
Peroxisomal ABC transporter are all homodimers and therefore called:
half-ABC transporters
ABC transporters are primarily found in _
bacteria
2ndary active transport is considered active transport because:
energy is used to establish a gradient (primary active transport) and stowaway moves against its gradient
Na+/glucose contransport functions how?
p-type pump creates gradient a passive channel or carrier allows ions/molecules to travel against their gradient
T/F: all glucose transport is ACTIVE
FALSE; PASSIVE
Na+/Ca++ exchanger functions how?
- p-type pumps (Na+/K+ and PMCA) keep Na+ and Ca++ outside the cell and K+ inside.
- Passive carrier (Na+/Ca++ exchanger) moves external Na+ down its concentration gradient and externalizes even more Ca++.
2ndary active symport system found in intestines and kidneys
Na+-amino acids cotransport
2ndary active antiport system found in the kidneys
Na+-H+ exchange (regulate pH)
