Facilitated and Active Transport

Question 1

What are the three main classes of membrane protiens

Answer 1

1. Channels
2. transporters
3. ATP powered pumps

Question 2

What are channels

Answer 2

They are ion small hydrphilic molecules flow down their concentration gated and they can either be non gated or gated

Question 3

What are the three transporters

Answer 3

You have three types a uniporter symporter and antiporters
all moving one molecule down the gradient

Question 4

What are channels (gates) and transporters called

Answer 4

Facilitated transports

Question 5

What does a uniporter do

Answer 5

Just has one molecule moving down the gradient

Question 6

What does a symporter do

Answer 6

Move one molecule agaisnt the gradient and one down the gradient but in the same direction

Question 7

what does an antiporter do

Answer 7

Moves one molecule against the gradient and one down the gradient but in opposite directions

Question 8

What is an ATP-powered pump

Answer 8

Uses the energy of ATP hydrolis to move a variety of ions and small molecules agianst their concentration

Question 9

What is the driving force of facilitated transporters

Answer 9

Concentration gradient atp is not required but could be used to set up concentration gradient

Question 10

What are the two things facilitated transporters are

Answer 10

Specific
Saturable (have a limit to how fast they can do things)

Question 11

What are the two ways channels can be

Answer 11

Either open
or gated so that they are closed or open but this is not due to ligand binding but due to chemical or electrica signals

Question 12

What is an example of a voltage gated channel

Answer 12

SR calicum is released when the muscles sends a shock the calcium rushes out and contributes to muscle contraction

Question 13

What make the potassium channel specefic

Answer 13

There are integral membrane protiens which create holes in the membrane large enough for solutes to pass through
Size-based exclusion- Hydrophilic interior to channel
Specificity can lead to membrane potential

Question 14

Why does only potassium interact with these channels

Answer 14

Because of the spacing the potassium is happy when it is surrounded by water it needs the energy withing the CG for it to want to go through the membrane because it is a similar energy state within the pore and the spacing of the oxygens line up perfectly so they are touching it will continue through

Question 15

Why won’t sodium go through the K pore

Answer 15

Because it is too small and it wont have enough interactions with the water that it will want to leave its natural state

Question 16

What is the potassium resting channel

Answer 16

The plasma membrane is freely permeable to potassium due to open resting channels not permeable to Na or Cl this is due to size based exclusion

Question 17

What is the resting channel like in resting state

Answer 17

There is no charge gradient but there is more potassium in the cytosol then the extracellular medium

Question 18

What happens once potassium flows inside the cell

Answer 18

There than becomes more potassium in the extracellular medium the cell

Question 19

What is the charge inside the membrane

Answer 19

Negative

Question 20

Why does the cell have a negative charge in a resting channel

Answer 20

Because potassium is leaking out and chlorine cant cross so it stays inside the cell

Question 21

What changes the shape of the transporter

Answer 21

Normally closed but open when the ligand bind which causes a confirmational change

Question 22

What is a v class pump

Answer 22

Pumps only hydrogen atoms

Question 23

What is an F class pump

Answer 23

Also pumps only hydrogen atoms from exoplasmic to cytosolic side

Question 24

What does a ABC pump

Answer 24

Many small molecules

Question 25

What does a P class pump

Answer 25

H, Na, K, Ca

Question 26

What are ABC pumps not restricted to

Answer 26

Ions they can export sugars,amino acids, peptides, protiens, phospholipids , cholesterol, toxin and foreign substances across a membrane not just plasma membrane

Question 27

What does Flippase do

Answer 27

Can flip fatty acids from one leaflet to the other leaflet this does not usally happen but flippase can make this happen

Question 28

What are the concentrations of inside and outside the cell

Answer 28

High concentration of potassium inside the cell
High concentration of sodium outisde the cell

Question 29

What is the P-class pump, Muscle Ca2+ - ATPase

Answer 29

It has reversible phosphorylation= conformational change
2 Ca out of the Cytosol per ATP releases calcium and get rid of calcium by ATPase out of the cytoplasm inot the SR membrane

Question 30

What does the P-class Pump, Na/K ATPase do

Answer 30

• All cells have low cytoplasmic NA and high cytoplasmic K levels
  Pumps potassium into the cell and sodium outside the cell
  3 sodium out and 2 potassium in per ATP

Question 31

How does the secondary active transport work

Answer 31

Use ion gradients genertaed by ATP-powered pumps then couple the free engery associated with these ions going back along their concentration gradient to the import or export of other molecules agaisnt their concentration gradient

Question 32

What makes up secondary active transport

Answer 32

• Antiporters and symporters
  Couples transport between two different-molecules not just ions

Question 33

What is the glucose symporter

Answer 33

There is energy available from the Na/K ATPase and the K resting channel
2 Na down the gradient one glucose against the gradient

Question 34

Where is the energy coming from in the transporting glucose

Answer 34

Sodium going down the concentration and coupled with the free enrgy coming from the electerical charge

Question 35

What makes the electerical gradient

Answer 35

Potassium resting channel