BSI Lecture 12 Membrane Transport

Question 1

the distribution of important substances in intracellular vs extracellular are _______.

Answer 1

asymmetrical

Question 2

An asymmetrical distribution indicates some form of _____ or _____ _______

Answer 2

concentration; extruding mechanism

Question 3

What 2 types of molecules can pass through the cell membrane? (Groups)

Answer 3

1) Small hydrophobic molecules (O2, CO2, N2, Benzene)

2) Small uncharged polar molecules (H2O, glycerol, ethanol)

Question 4

Larger uncharged polar molecules can easily cross the membranes. T or F

Answer 4

False, large uncharged polar molecules cannot easily pass through the membrane

Question 5

Can ions pass easily across the membranes?

Answer 5

No, ions or atoms that contain a charge cannot pass through the membrane

Question 6

A substance diffuses from an area of ____ concentration to ____ until a uniform concentration is achieved.

Answer 6

high; low

Question 7

Diffusion can only occur in ___ or ___ phases.

Answer 7

liquid; gas

Question 8

In water-based biological systems _____ is rapid but the path is convoluted as substances collide frequently.

Answer 8

diffusion

Question 9

Diffusion is effective over long (intracellular/cellular) but not over short distances. T or F

Answer 9

False, diffusion is better over smaller distances (1mm in diameter or less diffusion of O2 is sufficient)

Question 10

Diffusion time _______ by the square of the distance but _____ with increased area.

Answer 10

increases; decreases

Question 11

Diffusion time decreases the greater the concentration difference (greater potential energy). T or F

Answer 11

true

Question 12

Diffusion is more rapid the smaller the substance. T or F?

Answer 12

true

Question 13

Diffusion movement is due to ______ energy and therefore increases as temperature increases. Increased viscosity can also be a significant

Answer 13

kinetic

Question 14

When a concentration difference occurs across a membrane but the substance/solute is impermeable, WATER will move in the opposite direction in an attempt to equalize the concentrations, this is known as ______

Answer 14

osmosis

Question 15

Is osmosis energetically favorable?

Answer 15

yes

Question 16

Osmotic pressure depends on the ______ of solute particles only.

Answer 16

number

Question 17

A Molar solution of a substance that does not dissociate, exerts an osmotic pressure of ____.

Answer 17

1 osmole

Question 18

Dissociation into two ions, (as happens when NaCl is dissolved), ________ the osmotic pressure.

Answer 18

doubles

Question 19

What are the ways water can pass through the membranes.

Answer 19

1) it can pass directly through the membrane
2) Through hydrophilic “binding sites” of transporter/”pumps”
3) The aqueous “cores” of ion channels
4) Aquaporins

Question 20

The ______ pressure of bodily fluids, including cytoplasm is strictly regulated.

Answer 20

osmotic

Question 21

_________ solutions will move water out of cells and cause them to shrink.

Answer 21

hypertonic

Question 22

_________ solutions will move water into cells and cause them to swell or even burst/lyse.

Answer 22

hypotonic

Question 23

________ refers to equal osmotic pressure.

Answer 23

isotonicity

Question 24

Isotonicity must be maintained; what perform this task?

Answer 24

ion pumps

Question 25

Because of water's permeability it cannot be directly pumped/transported but must follow changes in osmotic pressure: typically NaCl is _____ and water _____.

Answer 25

pumped; follows

Question 26

______ exert osmotic pressure, (aka oncotic osmotic pressure), and this can be a significant factor especially in fluid exchange in capillaries

Answer 26

proteins

Question 27

________ pressure, (aka blood pressure), forces water out of capillaries but the oncotic pressure of the plasma proteins draws water back typically resulting in very little net fluid loss to the tissues.

Answer 27

hydrostatic

Question 28

To move non-permeable solutes across membranes requires some form of _______ _______ that permits movement of ions or molecules across the lipid bilayer.

Answer 28

transport system

Question 29

Transmembrane proteins can either form _____ channels or _________/pumps.

Answer 29

aqueous; transporters

Question 30

Aqueous channels typically allow ions to flow ______ their electrochemical gradients.

Answer 30

down

Question 31

Ion flow not only depends on concentration differences but also the _______ potential across the membrane.

Answer 31

electrical

Question 32

If the flow is down the concentration or electrochemical gradient it is termed passive or facilitated transport and requires no energy, what supplies the energy?

Answer 32

the gradient supplies the potential energy

Question 33

The flow against the concentration or electrochemical gradient it is termed ______ _______ and requires energy (usually ATP)

Answer 33

active transport

Question 34

If _____ _____ of one solute is linked to the transport of another solute it is said to be coupled.

Answer 34

passive transport

Question 35

If an active transport of one solute is linked to the transport of another solute it is called _______ _______ _______..

Answer 35

secondary active transport

Question 36

Transport of a substance in one direction is termed ____

Answer 36

uniport

Question 37

Transport of two or more substances in the same direction is termed _______

Answer 37

symport

Question 38

Transport of two or more substances in opposite directions is termed ______

Answer 38

antiport

Question 39

If _______ ________ is maintained by either transporting equivalent positive and negative ions, (for example Na+ with Cl- as in many epithelial cells), or exchanging ions with the same charge, (HCO3- out/Cl- in as in red blood cells), only the concentration gradient matters.

Answer 39

electrical neutrality

Question 40

Unlike for membrane-permeable substances, transported substances rely on a finite number of transporting proteins and therefore are subject to _____ _______

Answer 40

saturation kinetics

Question 41

Comparing the osmotic pressure of molar solutions, which solute would exert the least pressure? A. One that dissociated fully B. One that partially dissociated C. One that did not dissociate

Answer 41

C. One that did not dissociate

Question 42

Moving ions out of a cell will do what to its osmotic pressure? A. Increase it B. Not change it C. Decrease it

Answer 42

C. Decrease it

Question 43

Diffusion of a freely membrane permeable substance exhibits saturation kinetics? A. True B. False

Answer 43

B. False

Question 44

Transport utilizing a carrier exhibits saturation kinetics? A. True B. False

Answer 44

A. True

Question 45

Ion channels do not exhibit saturation kinetics? A. True B. False

Answer 45

A. True

Question 46

Which direction of net flux does diffusion through lipid bilayer go?

Answer 46

High to low concentration

Question 47

Diffusion through the bilayer is at equilibrium state or steady state.

Answer 47

Equilibrium

Question 48

Diffusion through the bilayer, does it use integral membrane protein.

Answer 48

no

Question 49

Diffusion through the bilayer, does it produce maximum flux at high concentration?

Answer 49

no

Question 50

Diffusion through the bilayer, is it chemical specific?

Answer 50

no

Question 51

Diffusion through the bilayer, does it use energy and source?

Answer 51

no

Question 52

What are the typical molecules using diffusion through the bilayer?

Answer 52

Nonpolar: O2, CO2, fatty acids

Question 53

Facilitated diffusion, what is the direction of net flux?

Answer 53

high to low concentration

Question 54

Facilitated diffusion, is it at _____ or at steady state?

Answer 54

equilibrium

Question 55

Facilitated diffusion, does it use integral membrane protein?

Answer 55

yes

Question 56

Facilitated diffusion, does it achieve maximal flux at high concentration.

Answer 56

yes

Question 57

Facilitated diffusion, does it use energy and source?

Answer 57

no

Question 58

Facilitated diffusion, what are the typical molecules?

Answer 58

polar: glucose

Question 59

Primary active transport, what is the direction of net flux?

Answer 59

low to high concentration

Question 60

Primary active transport, is it a equilibrium or at steady state?

Answer 60

steady state

Question 61

Primary active transport, does it use integral membrane protein?

Answer 61

yes

Question 62

Primary active transport, does it achieve maximal flux at high concentration?

Answer 62

yes

Question 63

Primary active transport, are they chemical specific?

Answer 63

yes

Question 64

Primary active transport, do they use energy and source?

Answer 64

yes, ATP

Question 65

Primary active transport, what are the typical molecules?

Answer 65

Ions: Na+, K+, Ca2+, H+

Question 66

Secondary active transport, what is the directional of net flux?

Answer 66

Low to high concentration

Question 67

Secondary active transport, is it a equilibrium or steady state?

Answer 67

steady state

Question 68

Secondary active transport, does it use integral membrane protein?

Answer 68

yes

Question 69

Secondary active transport, does it achieve maximal flux at high concentration?

Answer 69

yes

Question 70

Secondary active transport, are they chemical specific?

Answer 70

yes

Question 71

Secondary active transport, does it use energy and source?

Answer 71

yes, often ion gradient (Na+)

Question 72

Secondary active transport, what are the typical molecules?

Answer 72

Polar: amino acids, glucose, and some ions