Module 9 - 4

Question 1

What is uniport?

Answer 1

Transport of a single molecule.

Question 2

What is an antiporter?

Answer 2

Moves molecules in different directions.

Question 3

What is a symporter?

Answer 3

Moves molecules in the same direction.

Question 4

What is the role of charge in co-transport?

Answer 4

To have a net neutral change.

Question 5

What is secondary active co-transport?

Answer 5

Couples a molecule moving down its gradient to one moving down its gradient.

Question 6

What is active transport?

Answer 6

Movement of molecules against concentration gradients.

Question 7

What is primary active transport?

Answer 7

Driven by direct source of energy (ATP).

Question 8

What are the types of primary active transport?

Answer 8

P-, V-type, and ABC Transporters.

Question 9

What is secondary active transport?

Answer 9

Couples the movement of one molecule down its concentration gradient within the movement of another molecule down its gradient.

Question 10

What is the role of Na+ and K+ in cells?

Answer 10

Maintains high gradients to control cell volume, electrical excitability, and enables uptake of nutrients.

Question 11

What percentage of ATP is used to fuel the Na+-K+ pump?

Answer 11

40%.

Question 12

What is the energy requirement to maintain activity of the Na+-K+ pump?

Answer 12

About a third of your energy.

Question 13

What is the role of Na+,K+ ATPase?

Answer 13

Uses the energy of ATP hydrolysis to pump three Na+ out of the cell and two K+ into the cell.

Question 14

What is a P-type transporter?

Answer 14

Undergoes a phosphorylated intermediate.

Question 15

What are V-type ATPases?

Answer 15

Use the energy of ATP to move protons against a concentration gradient.

Question 16

What is the role of V-type ATPases in organelles?

Answer 16

Acidification of organelles.

Question 17

What is the role of F-type ATP Synthases in chloroplasts and mitochondria?

Answer 17

Reverse the reaction to use proton gradients to generate ATP.

Question 18

What are ABC Transporters?

Answer 18

Contain ATP-binding domains and transport a variety of biomolecules out of the cell against a concentration gradient.ac

Question 19

What is the function of multi-drug resistance protein?

Answer 19

Pumps drugs out of the cell

Question 20

What is the secondary active transport mechanism for glucose uptake in intestinal epithelial cells?

Answer 20

Symport with Na+

Question 21

What enables the movement of glucose up its concentration gradient in intestinal epithelial cells?

Answer 21

Movement of Na+ ions down their concentration gradient

Question 22

What is the role of Na+-K+ ATPase in glucose uptake from the gut?

Answer 22

Establishes the gradient of Na+ ions

Question 23

What is the function of ion channels?

Answer 23

Enable rapid movement of ions across the membrane

Question 24

What is the effect of ion channels on neurons?

Answer 24

Cause changes in membrane potential (action potentials)

Question 25

How are ion channels regulated?

Answer 25

Voltage-gated and ligand-gated channels

Question 26

How do ion channels differ from ion transporters?

Answer 26

Faster, no saturation limits, gated/regulated

Question 27

What is the selectivity of ion channels?

Answer 27

Highly selective for the molecule to be transported

Question 28

What is the function of K+ channel?

Answer 28

Allows rapid movement of K+ ions out of cell

Question 29

What is the selectivity filter in K+ channel?

Answer 29

Discriminates K and Na based on their ability to shed water molecules to form electrostatic interactions within backbone carbonyls

Question 30

How many equivalent binding sites does the selectivity filter in K+ channel have?

Answer 30

Four

Question 31

What is the effect of electrostatic repulsion from other incoming K+ ions on the flow of ions in K+ channel?

Answer 31

Helps to push the flow of ions from inside to outside the cell