Principals Of Physiology: Chapter 5 - Membrane Transport

Front 1

List the two types of membrane transport.

Back 1

1) Passive transport
2) Active transport

Front 2

List the two types of passive transport.

Back 2

Two types of passive transport:
1) Simple diffusion
2) Passive transport (aka "facilitated diffusion")

Front 3

List the two types of active transport.

Back 3

Two types of active transport:
1) Primary active transport
2) Secondary active transport

Front 4

What kind of transport is simple diffusion?

Back 4

Simple diffusion = passive transport

Front 5

What kind of transport is facilitated diffusion?

Back 5

Facilitated transport = passive transport

Front 6

What is another name for facilitated diffusion?

Back 6

Facilitated transport aka passive transport

Front 7

What happens in simple diffusion?

Back 7

Macro: Solute moves toward equilibrium without any inputted energy.

Front 8

What does simple diffusion need in order to occur?

Back 8

1) Concentration gradient
2) Solute encounters the plasma membrane
3) Solute can pass through the plasma membrane

Front 9

True or false?

A higher concentration gradient ='s greater movement of solutes.

Back 9

True.

A higher concentration gradient ='s greater movement of solutes.

Front 10

What doesn't simple diffusion need?

Back 10

Simple diffusion doesn't need transmembrane proteins/channels.

Front 11

Solutes can cross the membrane by simple diffusion if and only iff...

Give examples of what molecules can cross the cellular membrane via simple diffusion.

Back 11

1) Solute's H-bonds can be broken
2) Solute is lipid soluble

Examples of molecules that can undergo simple diffusion across a cellular membrane:
* Single -OH alcohols (e.g. methanol. ethanol)
* Steroid hormones (e.g. estrogen, progesterone, testosterone, cortisol)

Front 12

Rate of diffusion (J) formula:

J = dQs/dT --> D(C1 - C2)/x

What does each symbol mean?
D, C1, C2, X

Back 12

D = diffusion coefficient
C1 = Higher concentration
C2 = Lower concentration
X = Distance between C1 and C2

Front 13

What is the unit for the rate of diffusion (J)?

Back 13

Unit for rate of diffusion:

Joules = moles/(cm^2*s)

Front 14

Rate of diffusion (J) formula:

J = dQs/dT --> P(C1 - C2)

What is P?

Back 14

P = permeability constant = D/X

* D = Diffusion coefficient
* X = Distance between C1 and C2

Front 15

Diffusion is dependent upon which 5 characteristics?

Back 15

Diffusion is dependent upon:
- Molecular weight
- Size
- Polarity
- Solubility
- Molecular shape

Front 16

What is the best predictor of diffusion?

What is it related to?

Back 16

The best predictor of diffusion is the partition coefficient, K.

The partition coefficient, K, is proportional to P (the permeability constant).

Front 17

How do hydroxyl groups help diffusion?

*Note: There are two.

Back 17

Hydroxyl groups help diffusion by:
- Facilitating H-bonding to water
- Decreases lipid solubility

Front 18

Determine if each of the characteristics below are increased or decreased for molecules with: (a) more -OH substituents, and (b) less -OH substituents.

1) Hydrogen-bonding capacity
2) Water solubility
3) Lipid solubility

Back 18

Front 19

What does facilitated diffusion need in order to occur?

*Note: There are two things.

Back 19

Facilitated diffusion needs:
1) Electrochemical gradient
2) Specialized membrane proteins

Front 20

What are the two types of specialized membrane proteins needed by facilitated diffusion?

Back 20

- Channels and pores
- Carrier proteins

Front 21

What is the difference between how a solute enters a cell through: (1) channels and pores, and (2) carrier proteins.

Back 21

1) Channels and pores: Solutes diffuse down its electrochemical gradient.

2) Carrier proteins: There is a conformational change with binding of the transported molecules.

Front 22

List the three types of facilitated transport.

Back 22

Three types of facilitated transport:
1) Uniporter
2) Symporter
3) Antiporter

Front 23

List the two types of co-transport.

Back 23

Two types of co-transport:
1) Symporter
2) Antiporter

Front 24

Draw a graph of the rate of influx for each of the following:

1) Passive diffusion through a membrane
2) Passive transport through channels
3) Carrier-mediated transport (passive or active)

Back 24

Front 25

What is passive diffusion (through membranes) important for? Give examples of each.

Back 25

Passive diffusion through membranes is important for:
- Small compounds (e.g. O2, CO2)
- Lipid soluble compounds (e.g. ethanol, cortisol, testosterone, progesterone, estrogen)

Front 26

What is passive transport through channels important for?

Back 26

Passive transport through channels is important for:
- Ions

Front 27

What is carrier-mediated transport (either passive or active) important for?

Back 27

Carrier-mediated transport (either passive or active) is important for:

- Ions
- Larger compounds
- Water soluble compounds

Front 28

Back 28

The rate of diffusion has a similar curve to that of enzymes.

Front 29

List the four types of ion channels.

Back 29

Four types of ion channels:

1) Voltage-gated
2) Phosphorylation-gated
3) Stretch-gated / tension-gated
4) Ligand-gated

Front 30

Draw diagrams of each of the four types of ion channels.

Back 30

Front 31

What does the Nernst equation describe?

Back 31

The equilibrium potential; the potential for and degree by which the atom will diffuse.

Front 32

What two forces act on ions within a cell?

Back 32

Two forces that act on ions within a cell:
1) Chemical gradients
2) Electrical gradients

The sum of these two things make up a cell's electrochemical gradient.

Front 33

Describe the Donnan equilibrium.

Back 33

...

Front 34

Describe the relative abundance of each ion in the internal and external cellular environments.

1) K+
2) Na+
3) Ca+2
4) Cl-

Back 34

1) [K+] cytosol > [K+] extracellular fluid

2) [Na+] cytosol < [Na+] extracellular fluid

3) [Ca+] cytosol < [Ca+2] extracellular fluid

4) [Cl-] cytosol < [Cl-] extracellular fluid

Front 35

List the two types of active transport.

Back 35

Types of active transport:

1) Primary active transport
2) Secondary active transport

Front 36

Define each type of active transport.

Back 36

1) Primary active transport
Is ATP dependent because substance will be transported against its electrochemical gradient.

2) Secondary active transport
Ion moving with its electrochemical gradient provides the energy needed to move another substance against its electrochemical gradient.

Front 37

Name what substances primarily use each type of transport. Provide examples of each types of transport in detail.

Back 37

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