Module 1: Lecture 8

Question 1

what is active transportation?

Answer 1

requires the use of energy

Question 2

when is active transportation used?

Answer 2

when moving from low to high concentration (against the concentration gradient)

Question 3

what are the two types of carrier-mediated transport?

Answer 3

• active transport (requires energy)
• passive transport (does not require energy)

Question 4

what is affinity?

Answer 4

the shape of a binding site to allow something specific to bind
- the attraction to a molecule

Question 5

how does active transport selectively move molecules from low to high concentration?

Answer 5

it uses energy to change the shape of the pumps binding site so that only things from low concentration can bind and then once it flips, it changes shape again to make sure nothing can fit it in to come to the low concentration side

Question 6

what is ATPase?

Answer 6

an enzyme that breaks down ATP into ADP and the high energy phosphate

Question 7

how does energy change the shape of the transporter pumps binding site during active transport?

Answer 7

the high energy phosphate from ATP binds to the pump and the phosphate changes the pumps shape. allows it to flip and change the affinity from high to low affinity

Question 8

what is primary active transport?

Answer 8

energy (ATP) is DIRECTLY required to move a substance against the concentration gradient

Question 9

the carriers for primary active transport are called?

Answer 9

pumps

Question 10

what are the two types of primary active transporters?

Answer 10

1. single type of passenger (only moves one type of ion)
2. two different substances within the same carrier. different binding pockets (either simultaneously in same direction or sequentially in opposite direction)

Question 11

where is sodium more concentrated in our cells?

Answer 11

outside plasma membrane

Question 12

where is potassium more concentrated in our cells?

Answer 12

inside plasma membrane

Question 13

why do we concentrate ions on different sides of the membrane?

Answer 13

to create potential for electric impulses

Question 14

the sodium-potassium pump has how many pockets for each molecule?

Answer 14

3 pockets for sodium and 2 pockets for potassium

Question 15

when there is a low concentration of a molecule on one side, is affinity for that molecule high or low?

Answer 15

high. it wants to attract it more

Question 16

why do we take 3 sodium out and two potassium in with the Na-K pump?

Answer 16

for the electrical gradient. both are positively charged so if we have 3 sodium, its more positive than the 2 potassium (3+ vs 2+)

Question 17

a single nerve cell membrane contains about ________ Na+-K+ pumps capable of transporting about ____________ ions per second?

Answer 17

1. one million
2. 200 million

Question 18

what is secondary active transport?

Answer 18

using energy (ATP) indirectly. it used the potential from sodium which was built using ATP

Question 19

what are the two types of secondary active transporters?

Answer 19

1. symport (cotransport): move both molecules in same direction (Na+ and the solute)
2. antiport(counter-transport): the solute and Na+ move through the membrane in opposite directions