transport mechanisms

Question 1

Does facilitated diffusion need ATP?

Answer 1

no, it is driven by a conc gradient

Question 2

Which form of difussion displays saturation kinetics?

Answer 2

faciliated

Question 3

Which of the transport mechanism is not rate-limited by an intrinsic Vmax?

Answer 3

Simple diffusion

Question 4

Which transport ar limited by Vmax *

Answer 4

Facilitated diffusion and both primary and secondary active transport all involve protein transporters or carriers

Question 5

The rate of______is linear with solute concentration. *

Answer 5

simple diffusion

Question 6

Voltage-gated channels are ___-specific and open in response to a change in membrane voltage.

Answer 6

ion*

Question 7

Facilitated diffusion is a passive process. Entry of S into the cell will dissipate the concentration gradient and drive the process toward

Answer 7

equilibrium (no net flux of S).

Question 8

When distances reach 1 cm or greater a significant movement can occur only with

Answer 8

pressure differences, *

Question 9

selective passage of ____ solutes is mediated by membrane proteins

Answer 9

hydrophilic

Question 10

the electrochemical potential (potential to due work when the electrochemical portial exists across the membraen) is dependent on

Answer 10

solute activity, charge and valence, and the electrical potential difference across a membrane

Question 11

The difference in electrochemical potential reflects 1. the magnitude of the difference in transmembrane solute _____ \n2. the difference in trans-membrane ____ factored by the charge \n3. and _______ of the solute.

Answer 11

concentration \n\nvoltage\n\nvalence

Question 12

for ______ solutes without charge trans-membrane solute free energy differences is NOT CHANGE by a trans-membrane electrical potential difference

Answer 12

neutral (like nonelectrophyres

Question 13

Active transport is defined as movement of a solute from a place of low to high _____ potential

Answer 13

electrochemical

Question 14

thermodynamic equilibrium is the absence of a solute____ across the membrane

Answer 14

electrochemical potential difference

Question 15

At thermodynamic equilibrium, mechanisms that are passive mediate equal ____ solute transport in the forward and reverse direction across the membrane \n\n\nresulting in no net transport.

Answer 15

unidirectional

Question 16

For electrolytes such as anionic and cationic ions, thermodynamic equilibrium occurs when the___ and _____ driving forces acting on solute transport are equal and opposite in direction across the membrane

Answer 16

chemical and electrical \n\nthe net force is zero

Question 17

For ____ an electrical driving force does not apply

Answer 17

non-electrolytes

Question 18

for nonelectrolytes thermodynamic equilibrium occurs in the absence of a _____ gradient where trans-membrane solute concentrations are equal.

Answer 18

solute concentration

Question 19

for electrolytes and nonelectrolytes\n\nwhere unidirectional solute transport is _____ across the cell membrane, no net transport occurs and the charged

Answer 19

equal and opposite

Question 20

presence of solute active transport mechanisms in the cell membrane permit a___ steady state

Answer 20

non-equilibrium solute

Question 21

when a solute is in a nonequilbrium solute steady state \n\nthe solute is in ___ but the ____ is equal

Answer 21

electrochemical disequilbrium\n\n\nunidirectional solute transport\n

Question 22

what is the 3D concept of a gradient include

Answer 22

difference\ndirection\ndriving force

Question 23

The thermodynamic classification requires consideration of a solute_s _____ on either side of the cell membrane and a possible ______ in solute electrochemical potential across the cell membrane.

Answer 23

electrochemical potential ; difference in electrochemical potential

Question 24

solute electrochemical potential is a a funciton of its

Answer 24

concentration and charge

Question 25

* an ____ solute is described by a chemical potential not an electrochemical potential

Answer 25

uncharged (liek glucose)

Question 26

he source of the required energy arises in active transport fcomes from ____ in secondary active transport

Answer 26

a coupling to a second solute,

Question 27

ion translocating pump is ____ transport

Answer 27

primary active

Question 28

a channel does ___ transport

Answer 28

passive

Question 29

3 types of carriers\n\n uniporter, ____, and ____

Answer 29

uniporter, symporter, antiporter

Question 30

uniporter does ___ trnasport

Answer 30

passive

Question 31

symposter does ____ transport

Answer 31

secondary active

Question 32

atniporter does ____ transport

Answer 32

secondary active

Question 33

in secondary active transport one solute is moving _____ its electrochemical potential gradient, driving or pushing the second solute up or against its electrochemical potential gradient.

Answer 33

down

Question 34

The inwardly directed Na electrochemical potential gradient is the most common driving force for ____ transport

Answer 34

secondary active symporter

Question 35

Non-mediated transport is defined as ___.

Answer 35

Simple Diffusion

Question 36

Mediated transport occurs by three different transport mechanisms:

Answer 36

Channels, Carriers and Pumps

Question 37

Channel mediated transport is ___ trnasport

Answer 37

passive

Question 38

Carrier mediated transport by Facilitated Diffusion or Uniport is ____ transport

Answer 38

passive

Question 39

Even though they both do passive transport Channel mediated and Uniporter mediated transport have very different and distinct ____ properties

Answer 39

functional

Question 40

cotransport or symport is ____ transport

Answer 40

secondary active

Question 41

pump is ___ transport

Answer 41

primary active

Question 42

____ diffusion does NOT occur by interaction with, or mediation by, the presence of a transport protein

Answer 42

simple

Question 43

secondary active transport proteins may occur in the same direction across the membrane via ____ cotransport

Answer 43

symport

Question 44

Passive membrane transport of solutes occurs across the membrane until ____ is reached and ____

Answer 44

electrochemical potential equilibrium is reached\n\n and the solute electrochemical potential difference across the membrane is zero

Question 45

A process of ___ diffusion mediates passive solute transport by carrier proteins in the cell membrane

Answer 45

facilitated

Question 46

which is faster? channels or carrier mediated?

Answer 46

channels

Question 47

Na/K atpase results in net ____ charge transfer out of the cell

Answer 47

positive (this contriutes to negative charge in the cell)

Question 48

_Steady state_ distribution of Na and K across the cell membrane results from balancing the _leak_ of ___ and _____ with the active transport Na and K

Answer 48

Na into the cell and K out of the cell

Question 49

Km is the quntiation of ____ affinity

Answer 49

substrate

Question 50

Vmax or Jmax is the qunatitation of

Answer 50

maximal transport rate

Question 51

J x vs [X] is linear with ___ diffusion

Answer 51

simple

Question 52

With carrier mediated or faciliated fiussion km=___

Answer 52

1/2 J max

Question 53

all mediated transport mechanisms have ____ common to them

Answer 53

saturability

Question 54

simple diffusion does not demonstrate the property of ____

Answer 54

saturatbility

Question 55

he Vmax value is determined by the ____ of transporters present in the membrane and the time required for a transporter to undergo one complete transport cycle or turnover.

Answer 55

number of trnasporters and the time required

Question 56

Under these conditions the maximal velocity of solute transport is only as fast as the ____ of the transporter

Answer 56

conformational change (rate limiting step)

Question 57

ransport stoichiometry is defined as the number substrate molecules transported in

Answer 57

one complete cycle of molecular events

Question 58

the property of _____ confers membrane potential difference (voltage) as well as substrate concentration difference as an additional driving force favoring or opposing transport.

Answer 58

electrogenicity