4.4-ACTIVE TRANSPORT

Question 1

What is active transport?

Answer 1

movement of molecules/ions into or out of cell from region of lower concentration to region of higher concentration using ATP + carrier proteins

Question 2

What is ATP used to do in active transport? (2)

Answer 2

directly move molecules

individually move molecules using concentration gradient which has already been set up by (direct) active transport
known as co-transport

Question 3

How does active transport differ from passive transport? (4)

Answer 3

metabolic energy in form of ATP needed

substances moved against concentration gradient

carrier protein molecules which acts as “pumps” involved

process very selective, with specific substances being transported

Question 4

Process of direct active transport of single molecule/ion #1

Answer 4

carrier proteins span plasma membrane + bind to molecule/ion to be transported onto other side

Question 5

Process of directive active transport #2

Answer 5

molecule/ion binds to receptor sites on carrier protein

Question 6

Process of directive active transport #3

Answer 6

on inside of cell/organelle, ATP binds to protein, causing it to split into ADP + a phospholipid molecule

Question 7

What happens when the ATP molecule splits into ADP + a phospholipid molecule?

Answer 7

protein molecule changes shape + opens to opposite side of membrane

Question 8

Process of directive active transport #4

Answer 8

molecule/ion released to other side of membrane

Question 9

Process of directive active transport #5

Answer 9

phosphate molecule released from protein which causes protein to revert to its original shape, ready for process to be repeated
phosphate molecules then recombine with ADP to form ATP during respiration

Question 10

Similarity between facilitated diffusion and active transport?

Answer 10

both use carrier proteins

Question 11

Difference between facilitated diffusion and active transport?

Answer 11

facilitated diffusion occurs down a concentration gradient, while active transport occurs against concentration gradient

Question 12

As facilitated diffusion occurs down a concentration gradient, what does it not require but active transport does?

Answer 12

metabolic energy

Question 13

What is metabolic energy provided in the form of?

Answer 13

ATP

Question 14

What can sometime happen with the number of molecules/ions during active transport?

Answer 14

sometimes more than one molecule/ion may be moved in same direction at same time by active transport

Question 15

What can ocassionaly happen with molecules/ions moving in/out of cell/organelle?

Answer 15

molecule/ion moved into cell/organelle at same time as different one being removed from it

Question 16

What is an e.g. of when one molecule/ion enters cell/organelle while other leaves?

Answer 16

sodium-potassium pump

Question 17

Which ion is actively removed from cell/organelle in the sodium-potassium pump?

Answer 17

sodium ions actively removed from cell/organelle

Question 18

Which ions is actively taken from the surroundings in the sodium-potassium pump?

Answer 18

potassium ions actively taken in from surroundings

Question 19

What else uses a similar process to the sodium-potassium pump?

Answer 19

creation of a nerve impulse