Active Transport

Question 1

Def of active transport

Answer 1

Movement of molecules/ions in or out of a cell from a region of lower conc to a region of higher conc using ATP& carrier proteins

Question 2

Why is AT different from passive?

Answer 2

• metabolic energy needed (ATP)
• against conc gradient
• carrier protein molecules involved
• selective process

Question 3

Process of AT

Answer 3

• carrier proteins span plasma mem& bind to ion to be transported. Ion binds to receptor sites on CP
• on one side of cell, ATP binds to protein so it splits intonADP& phosp
• protein changes shape &opens to opp side of mem
• ion is released to other side of mem
• phos molecule is released so protein reverts to orig shape
• phos combines with ADP to form ATP in resp

Question 4

Sodium-potassium pump

Answer 4

• essential to create a nerve impulse

- sodium ions actively removed while K+ ions actively taken in fromsurroundings