Exam 3 Transport through Membranes I ACTIVE

Question 1

small and hydrophobic; how likely to cross lipid bilayer without any help?

Answer 1

easy to get across lipid bilayer

Question 2

small and polar; how likely to cross lipid bilayer without any help?

Answer 2

might get across lipid bilayer

Question 3

large and polar; how likely to cross lipid bilayer without any help?

Answer 3

will not cross lipid bilayer

Question 4

charged/ion; how likely to cross lipid bilayer without any help?

Answer 4

will not without help

Question 5

no energy required and solute travels from high to low concentration describes what type of transport?

Answer 5

passive

Question 6

main form of energy is ATP hydrolysis and we are either creating a concentration gradient or reinforcing it; describes what type of transport?

Answer 6

active

Question 7

what are the 3 general modes of transport

Answer 7

1. uniporter = moves 1 thing with no specificity on direction
2. symporter = same; movement of 2 things in same direction
3. antiporter = opposite; movement of 2 things in opposite direction

Question 8

what are the 3 general categories of transporters?

Answer 8

1. pumps = perform active transport; fights the concentration gradient
2. carriers = coupled to primary transport pump; 2ndary transport carriers
3. channels = passive transport

Question 9

what are the 2 types of primary active transport pumps?

Answer 9

1. p-type pump

2. ABC transporter

Question 10

what are the 4 pieces to a p-type pump to identify that is what being used in transport?

Answer 10

1. transmembrane domain spans the lipid bilayer
2. A/Actuator (hinge) links cytosolic domains to transmembrane domain
3. N/Nucleotide binding domain binds ATP
4. P/Phosphorylation domain accepts the phosphate from ATP

Question 11

E1 is open to _ side

Answer 11

cytosolic side; binds molecule

Question 12

E2 is open to _ side

Answer 12

“outside”; releases molecule and may/may not bind another type molecule

Question 13

Ca++ transport uses what mode and pump for transport?

Answer 13

uniporter a P-type

Question 14

what are the names for Ca++ transport pumps?

Answer 14

SERCA (muscle cells)
PMCA (plasma membrane)
SPCA (Golgi secretion pathway)

Question 15

Na+/K+ pump uses what mode and pump for transport?

Answer 15

antiporter a P-type

Question 16

Flippases uses what type of transport

Answer 16

p-type

Question 17

what is the goal of flippases?

Answer 17

to perform a transverse (flipping) motion within plasma membrane as to internalize lipids on exterior cell membrane or recycle endosomes on Golgi

Question 18

what is a common molecule to be internalized via flippase?

Answer 18

phosophatidylserine (PS)

Question 19

what is the general mechanism for p-type pumps?

Answer 19

capture (E1) -> ATP (self) -> eversion (E2) -> release -> bind something else (E2)

Question 20

in plants and fungi, Na+/K+ pump is replaced by

Answer 20

H+-ATPase

Question 21

what pump maintains the pH of the stomach lumen?

Answer 21

H+/K+-ATPase

Question 22

what pump maintains proper levels of trace metals?

Answer 22

Heavy Metal ATPases

Question 23

what are the 3 pieces to a ABC pump to identify that is what being used in transport?

Answer 23

• Duplicates*
  1. 2 transmembrane domains
  2. 2 Nucleotide biding domains for ATP
  3. importers require a substrate binding protein

Question 24

what is the goal of an ABC transporter?

Answer 24

to phosphorylate something else

Question 25

general mechanism of ABC transporter?

Answer 25

bind molecule (not ions!) -> ATP and dimerize -> eversion -> release molecule

Question 26

MDR proteins use what type of pump?

Answer 26

ABC; exporter used for drug resistance (incr MDR proteins = incr resistance)

Question 27

CTFR use what type of pump?

Answer 27

ABC; Cl- exporter

Question 28

what makes CTFR a noncanonical ABC transporter?

Answer 28

ATP hydrolysis is inefficient so acts live a passive/ligand-gated channel

Question 29

CTFR altered ion movement results in:

Answer 29

increased osmotic pressure which thus allows for secreted mucins to interact

Question 30

Peroxisomal ABC transporter are all homodimers and therefore called:

Answer 30

half-ABC transporters

Question 31

ABC transporters are primarily found in _

Answer 31

bacteria

Question 32

2ndary active transport is considered active transport because:

Answer 32

energy is used to establish a gradient (primary active transport) and stowaway moves against its gradient

Question 33

Na+/glucose contransport functions how?

Answer 33

p-type pump creates gradient a passive channel or carrier allows ions/molecules to travel against their gradient

Question 34

T/F: all glucose transport is ACTIVE

Answer 34

FALSE; PASSIVE

Question 35

Na+/Ca++ exchanger functions how?

Answer 35

- 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++.

Question 36

2ndary active symport system found in intestines and kidneys

Answer 36

Na+-amino acids cotransport

Question 37

2ndary active antiport system found in the kidneys

Answer 37

Na+-H+ exchange (regulate pH)