Cell Membrane Transport

Question 1

What are the two types of transport in driving forces?

Answer 1

passive and active transport

Question 2

Driving forces include ______ and ______ forces.

Answer 2

chemical and electrical forces

Question 3

Both chemical and electrical forces =

Answer 3

electrochemical force

Question 4

What is passive transport?

Answer 4

movement down the force

Question 5

What is active transport?

Answer 5

movement against the force

Question 6

Name 3 characteristics of driving forces.

Answer 6

• concentration​ ​gradient​ ​(ΔC):​ ​Difference​ ​in​ ​particle​ ​concentration​ ​between​ ​the​ ​inside and​ ​outside​ ​of​ ​the​ ​cell
• the​ ​gradient​ ​”pushes”​ ​particles​ ​from​ ​higher​ ​to​ ​lower​ ​concentration​ ​areas
• force​ ​acts​ ​from​ ​higher​ ​to​ ​lower​ ​concentration​ ​areas

Question 7

What is the direction of chemical driving force.

Answer 7

• down the chemical gradient

- from higher to lower concentration

Question 8

Define ion.

Answer 8

a charged particle

Question 9

Define cation.

Answer 9

​​particle​ ​with​ ​positive​ ​(+)​ ​charge,​ ​ex.​ ​Na+

Question 10

Define anion.

Answer 10

particle​ ​with​ ​negative​ ​(-)​ ​charge,​ ​ex.​ ​Cl-

Question 11

Define membrane​ ​potential​ ​(V​m)​.

Answer 11

​a​ ​force​ ​caused​ ​by​ ​unequal​ ​distribution​ ​of​ ​anions​ ​and​ ​cations across​ ​the​ ​cell​ ​membrane

Question 12

Membrane​ ​polarity​ ​(+​ ​or​ ​-)​ ​is​ ​determined​ ​by​…

Answer 12

net​ ​charge​ ​in​ ​the​ ​cell​ ​or​ ​intracellular reference

Question 13

Charge separation =

Answer 13

source of energy (difference across the membrane)

Question 14

Electrical driving force is measured in…

Answer 14

• millivolts
• represented​ ​by​ ​the​ ​…ve​ ​charge​ ​inside​ ​the​ ​cell
• ~​ ​-70​ ​mV​ ​(at​ ​rest)

Question 15

In electrical driving force, ______ charges attract.

Answer 15

opposite

Question 16

Direction of force in the electrical driving force depends on:

Answer 16

• polarity of the cell

- charge of the particle

Question 17

Magnitude of force in the electrical driving force depends on:

Answer 17

• Strength​ ​of​ ​the​ ​membrane​ ​potential​ ​(V​m)​

- Amount​ ​of​ ​charge​ ​on​ ​the​ ​particle (quality of charge, how much the ion carries)

Question 18

Describe passive transport.

Answer 18

• spontaneous
• no cell energy is required
• downhill movement

Question 19

What are the 3 types of passive transport?

Answer 19

• simple diffusion
• facilitated diffusion
• diffusion through channels

Question 20

What is simple diffusion?

Answer 20

• no membrane proteins needed

- transport through lipid bilayer

Question 21

What are the 6 factors affecting the rate of transport in simple diffusion?

Answer 21

• magnitude of the driving force
• membrane surface area
• membrane permeability
• thickness of the membrane
• lipid solubility of diffusing substance
• size and shape of diffusing particle

Question 22

What is facilitated diffusion?

Answer 22

passive transport through a carrier

Question 23

Give 4 characteristics of a carrier in facilitated diffusion.

Answer 23

• transmembrane protein
• binding sites: specific
• bind one at a time
• random conformational changes

Question 24

What are the 3 factors affecting the rate of transport in facilitated diffusion?

Answer 24

• rate of transport of the carrier
• number of carriers
• concentration gradient

Question 25

Where is GLUT4 synthesized?

Answer 25

rough ER

Question 26

Where is GLUT4 packaged?

Answer 26

vesicles

Question 27

_____ and _____ stimulates GLUT4 insertion.

Answer 27

insulin and exercise

Question 28

What happens with diabetes?

Answer 28

• lack of insulin action means less GLUT4
• decrease glucose uptake
• increase glucose in blood

Question 29

What is the increase of GLUT4 insertion with exercise called?

Answer 29

primary exercise effect

Question 30

What does exercise do to GLUT4 activity?

Answer 30

• increase (intrinsic)
• secondary effect
• technological limitations

Question 31

What kind of process is diffusion through channels?

Answer 31

passive

Question 32

Name 3 characteristics of diffusion through channels.

Answer 32

• transmembrane protein
• passageway or pore
• substance specific

Question 33

What are the 2 types of channels?

Answer 33

• aquaporins

- ion channels

Question 34

Describe aquaporins.

Answer 34

• H20
• Diffusion
• selective pores that permit water movement by diffusion

Question 35

What are the 2 parts of ion channels? Describe ion channels.

Answer 35

• leak channels and grated channels

- bidirectional: allows movement of ions in both directions

Question 36

Describe leak channels.

Answer 36

​allow​ ​Na+​ ​and​ ​K+​ ​to​ ​move​ ​down​ ​concentration​ ​gradients​ ​to maintain​ ​stable​ ​resting​ ​membrane​ ​potential

Question 37

Describe grated channels.

Answer 37

​chemical​ ​messenger​ ​binds,​ ​then​ ​channel​ ​allows​ ​ion​ ​through

Question 38

Rate of transport in ion channels depends on what 3 things?

Answer 38

• transport rate of each channel
• number of channels
• open or closed state