w6 membrane transport

Question 1

what are 3 types of extracellular fluid

Answer 1

blood plasma, interstitial fluid, transcellular fluid

Question 2

what is hematocrit

Answer 2

the fraction of blood volume that is occupied by RBC

Question 3

how is hematocrit determined

Answer 3

centrifuging blood that is treated w anticoagulant and measuring fraction of total volume that is occupied by packed RBC

Question 4

what separates the intravascule and interstitial compartments

Answer 4

walls of capillaries

Question 5

where is interstitial fluid found

Answer 5

outside the intravasculr compartment

Question 6

what does transcellular fluid count as

Answer 6

includes synovial fluid within joints, cerebrospinal fluid surrounding brain and spinal cord, fluid trapped within spaces that are completely surrounded by epithelial cells

Question 7

does transcellular fluid include fluids that are outside the body

Answer 7

no (gastrointestinal tract or urinary bladder doesnt count)

Question 8

intracellular fluid K+, Na+, Cl- levels low or high

Answer 8

high in K+, low in Na+ and Cl-

Question 9

extra cellular fluids (interstitial and plasma) K+, Na+, and Cl- levels

Answer 9

high in Na+ and Cl-, low in K+

Question 10

what direction is Na-K pump which goes in and out (and how many for each)

Answer 10

3 Na+ is leaving the cell to actively transport 2 K+ into the cell

Question 11

what is simple diffusion driven by

Answer 11

thermal motion of molecules
(proportional to concentration difference)

Question 12

osmosis

Answer 12

higher water [ ] to lower water [ ]
impermeable to solutes

Question 13

pores are

Answer 13

conduits that are always open

Question 14

channels are

Answer 14

conduits that are gated by a door

Question 15

carriers

Answer 15

conduits that never offers continuous transmembrane path bc it is equipped w at least 2 gates that are never opened at the same time

Question 16

primary active transport

Answer 16

directly coupled to the hydrolysis of ATP

Question 17

Na+/K+ alpha and beta subunit functions

Answer 17

alpha - mediates active transport
beta - essential for proper assembly of the pump

Question 18

does Na+/K+ pump use energy

Answer 18

yes

Question 19

E1 and E2 conformational states for Na+/K+ pump

Answer 19

E1 - binding sites for ions face the inside of the cell
E2 - binding sites face the outside

Question 20

model of action for Na+/K+ pump (which goes in or out first)

Answer 20

Na+ goes out first than K+ goes in

Question 21

what can block Na+/K+ pump

Answer 21

cardiac glycosides such as ouabin and digoxin (compete w K+ for binding)

Question 22

hypokalemia is low blood Na+ or K+

Answer 22

low blood K+

Question 23

what is the inside negative membrane voltage

Answer 23

~60mV

Question 24

H-K pump (HKA) is found where

Answer 24

parietal cells of the gastric gland

Question 25

HKA extrudes H+ where

Answer 25

extrudes H+ across the apical membrane into the gland lumen

Question 26

Ratio of HKA pump for K+,H+, ATP

Answer 26

uptake 2 K+, extrude 2H+, uses 1 ATP

Question 27

where are Ca2+ pumps found

Answer 27

plasma membrane of plasma membrane Ca2+-ATPase (PMCA cells)
SR and ER (play role in active sequestration of Ca2_ into intracellular stores)

Question 28

ratio and direction for ca2+ pump for H+,Ca2+, ATP

Answer 28

1 H+ for 1 Ca2+ for each hydrolyzed ATP
Ca2+ goes out, H+ goes in

Question 29

sarcoplasmic and endoplasmic reticulum calcium ATPase (SERCA) ratio

Answer 29

2 H+ and 2 Ca2+ for each ATP hydrolyzed
H+ goes out, Ca2+ goes in

Question 30

where are vaculolar-type (v-type H+ pump) found

Answer 30

intracellular organelles such as lysosomes, endosomes, secretory vesicles, storage vesicles, golgi apparatus

Question 31

V-type H+ pump pumps H+ what direction

Answer 31

from cytoplasm to interior of organelle (in)

Question 32

multidrug resistance transporters (MDRs)
MDR1 pumps what

Answer 32

pumps a wide range of anticancer drugs out of cancer cells, rendering cells resistant to these drugs

Question 33

secondary active transport

Answer 33

against the electrochemical gradient using energy in electrochemical gradient of other molecules to drive this transport

Question 34

3Na+-Ca2+ antiporter direction

Answer 34

secondary active transport of Ca2+
3Na+ in, 1Ca2+ out

Question 35

2 major classes of secondary active transporters

Answer 35

cotransporters (symporters)
exchangers (antiporters)

Question 36

cotransporters (symporter)

Answer 36

driving and driven solutes moving in SAME direction
generally driven by energy of inwardly directed Na+ garident

Question 37

cotransporter (symporter) example

Answer 37

sodium glucose linked transporter (SGLT)
sodium amino acid transporter

Question 38

exchanger (antiporter)

Answer 38

driving and driven solutes more in the OPPOSITE direction
(generally exchange + for + or - for -)

Question 39

example of exchangers/antiporter

Answer 39

sodium-calcium exchanger

Question 40

Na-Ca exchanger ratio and direction

Answer 40

3 Na+ per 2 Ca2+
moves net positive charge in same direction of Na+
inwardly directed Na+ drives Ca2+out of cell

Question 41

hypertonic vs hypotonic

Answer 41

hypertonic - water moving out of cell
hypotonic - water moving into cell

Question 42

isosmolal osmolality level
hyperosmolal
hypoosmolal

Answer 42

290 mOsm
hyper >
hypo <

Question 43

colloid osmotic pressure/oncotic pressure difference tends to pull water from what to what

Answer 43

from interstitium to plasma

Question 44

hydrostatic pressure difference across capillary wall drives fluid from where to where

Answer 44

from plasma to interstitium

Question 45

ultrafiltration

Answer 45

when hydrostatic pressure exceeds the colloid osmotic pressure and there is movement of water out of capillary