Cellular Membrane Transport

Front 1

What two things do cell membranes do?

Back 1

Separate fluids and allow exchange of materials

Front 2

Cell membranes are ________ permeable.

Back 2

Selectively permeable

Front 3

__________ allow the transport of some substances, but not others.

Back 3

Membranes

Front 4

How flexible is the membrane structure?

Back 4

Very flexible

Front 5

Permeability of the cell membrane determines what?

Back 5

Which substrates can enter and leave the cytosol

Front 6

Impermeable cell membrane

Back 6

Nothing crossing the cell membrane

Front 7

Freely permeable cell membrane

Back 7

Substances crossing the cell membrane with ease

Front 8

Selectively permeable cell membrane

Back 8

Permits free passage of some materials and restricts passage of others

Front 9

Cells differ in their permeabilities according to what two things?

Back 9

Variations in organization and identity of membrane lipids and proteins

Front 10

What are the two types of transport?

Back 10

Passive and active

Front 11

Passive transport is _________ (spontaneous or not) with __________ (up or downhill) movement.

Back 11

Spontaneous; downhill

Front 12

Active transport is __________ (spontaneous or not) with __________ (up or downhill) movement.

Back 12

Not spontaneous; uphill

Front 13

Driving forces

Back 13

Forces which act to move particles

Front 14

What are the two kinds of driving forces?

Back 14

Chemical and electrical

Front 15

Passive driving force

Back 15

Movement down the force

Front 16

Active driving force

Back 16

Movement against the force

Front 17

Chemical driving forces act from ________ to _______ concentration.

Back 17

Higher; lower

Front 18

What is the direction of a chemical driving force?

Back 18

Down the chemical gradient; higher to lower

Front 19

Ion

Back 19

Charged particle

Front 20

Cation

Back 20

Particle with a positive charge

Front 21

Anion

Back 21

Particle with a negative charge

Front 22

Membrane potential

Back 22

Force that comes about due to an unequal distribution of anions and cations across a cell membrane

Front 23

What is the source of energy for membrane potential?

Back 23

Charge separation

Front 24

The direction of force depends on what? (2)

Back 24

Polarity of cell and charge on particle

Front 25

Magnitude

Back 25

Sum of chemical force and the electrical force

Front 26

Passive transport

Back 26

Particles move from high to low force

Front 27

Active transport

Back 27

Particles move from low to high force

Front 28

When would a particle not be transported across a membrane, even if it is permeable to that particle?

Back 28

When equilibrium is reached

Front 29

Cells like to use _________ transport whenever possible because it conserves ATP.

Back 29

Passive

Front 30

What are three types of passive transport?

Back 30

Simple diffusion, facilitated diffusion, diffusion through channels

Front 31

Transport is through what layer in simple diffusion?

Back 31

Bilipid layer

Front 32

How many membrane proteins are needed for simple diffusion?

Back 32

None

Front 33

What are the three factors affecting the rate of simple diffusion?

Back 33

Magnitude of driving force, membrane surface area, and membrane permeability

Front 34

Diffusion

Back 34

A random movement of ions and molecules to evenly distribute said ions and molecules over time until equilibrium is reached

Front 35

The rate of oxygen diffusion into the cell _______ (increases or decreases) as needed.

Back 35

Increases

Front 36

The higher the temperature, the __________ (faster or slower) diffusion rate.

Back 36

Faster

Front 37

What charge does the inside of a cell have in comparison to the outside of the cell?

Back 37

Negative charge

Front 38

Water always travels ________ (up or down) its concentration gradient, unless energy is added to the system.

Back 38

Down

Front 39

What acts as a barrier and will restrict diffusion.

Back 39

Cell membrane

Front 40

In the ECF, water and dissolved solutes dissolve how?

Back 40

Freely

Front 41

Why is diffusion in the body fluids important?

Back 41

It tends to eliminate local concentration gradients

Front 42

The ___________ (larger or smaller) the concentration gradient, the faster diffusion proceeds.

Back 42

Larger

Front 43

The larger the concentration gradient, the __________ (faster or slower) diffusion proceeds.

Back 43

Faster

Front 44

The _______ (higher or lower) the permeability, the more energy required.

Back 44

Higher

Front 45

Facilitated diffusion

Back 45

Passive transport through a carrier

Front 46

Carrier

Back 46

A transmembrane protein that has binding sites for specific particles

Front 47

The molecule to be transported has to first do what?

Back 47

Bind to a receptor site on the protein

Front 48

What is not expended in facilitated diffusion?

Back 48

ATP

Front 49

Saturation of the channel

Back 49

When each channel is full and contains a glucose

Front 50

All cells move glucose across their membranes through what process?

Back 50

Facilitated diffusion

Front 51

The glucose transporter functions only when stimulated by what hormone?

Back 51

Insulin

Front 52

Osmosis

Back 52

Diffusion of water through a membrane

Front 53

What are three characteristics of osmosis?

Back 53

It's always passive, it is unaffected by membrane potentials, and it is driven by a water gradient

Front 54

Osmosis is a special case involving only what?

Back 54

Water

Front 55

"Osmos" is a latin term meaning what?

Back 55

Thrust

Front 56

Each solute tends to diffuse as if it were what?

Back 56

The only material in the solution

Front 57

Some solutes diffuse where?

Back 57

In the cytoplasm

Front 58

What is osmosis' ultimate goal?

Back 58

Water equillibrium

Front 59

Whenever solute concentration exists, there is also a concentration ingredient for what?

Back 59

Water

Front 60

The _________ (higher or lower) the solute concentration, the __________ (higher or lower) the water concentration.

Back 60

Higher; lower

Front 61

Osmotic pressure _________ (pushes or pulls). Hydrostatic pressure ________ (pushes or pulls).

Back 61

Pulls; pushes

Front 62

The __________ (greater or lesser) the initial difference in solute concentration, the _________ (stronger or weaker) the osmotic flow.

Back 62

Greater; stronger

Front 63

Osmotic pressure

Back 63

An indication of the force of water movement into a solution as a result of its solute concentration

Front 64

When water molecules cross a membrane, they move in groups held together by what kind of bonding?

Back 64

Hydrogen

Front 65

Bulk flow

Back 65

Water molecules crossing the membrane in large numbers

Front 66

Osmolarity

Back 66

The total solute concentration in an aqueous solution; osmotic concentration

Front 67

Isosmotic solution

Back 67

A solution that contains solutes in the same concentration as cytosol

Front 68

Osmolarity

Back 68

Total solute concentration of a solution

Front 69

Hypoosmotic solution

Back 69

A solution with a lower solute concentration than that of the cytosol

Front 70

Hyperosmotic solution

Back 70

A solution with a higher solute concentration than that of the cytosol

Front 71

Osmotic pressure

Back 71

Pulling pressure based on the solute concentration (water goes towards higher level of concentration)

Front 72

Osmotic pressure is based on what?

Back 72

The direction water flows

Front 73

Carrier-mediated transport

Back 73

Where integral proteins bind specific ions or organic substrates and facilitate their movement across the cell membrane

Front 74

Cotransport (symport)

Back 74

Where carrier transports two different substances in same directions simultaneously

Front 75

Countertransport (antiport)

Back 75

Where one substance moves into the cell and the other moves out simultaneously

Front 76

Aquaporins

Back 76

Pores that allow water to freely move

Front 77

Where does active energy gain its energy from?

Back 77

High energy compounds

Front 78

In active transport, the high-energy bond in _______ provides the energy needed to move ions or molecules across the membrane.

Back 78

ATP

Front 79

What one great advantage does active transport offer?

Back 79

It can import or export specific substrates regardless of their intra or extracellular concentrations

Front 80

___________ and ___________ are principal cations in body fluids.

Back 80

Sodium; potassium

Front 81

Homeostasis within the cell depends on what?

Back 81

The ejection of sodium ions and recapture of loss potassium ions

Front 82

For each ATP molecule used, ________ is/are ejected and ________ is/are reclaimed by the cell.

Back 82

3 sodium ions; 2 potassium ions

Front 83

Vesicular transport

Back 83

When materials move in or out of the cell by means of vesicles

Front 84

Vesicles

Back 84

Small membranous sacs that form at or fuse with the cell membrane

Front 85

What are the two major categories of vesicular transport?

Back 85

Endocytosis and exocytosis

Front 86

Endocytosis

Back 86

Packaging of extracellular materials in a vesicle at the cell surface for import into the cell; requires ATP

Front 87

Pinocytosis

Back 87

"Cell drinking;" formation of small vesicles filled with extracellular fluid

Front 88

Phagocytosis

Back 88

"Cell eating;" produces vesicles containing solid objects

Front 89

Pseudopodia

Back 89

Cytoplasmic extensions that surround the object and their membranes to form a vesicle

Front 90

Phagosome

Back 90

Vesicle formed by pseudopodia

Front 91

Exocytosis

Back 91

Where a vesicle created inside the cell fuses with the cell membrane and discharges its contents into the extracellular environment