4.4 Active transport

Question 1

Define active transport.

Answer 1

the movement of ions/molecules into or out of a cell up a concentration gradient using ATP and carrier proteins

Question 2

How does active transport differ from passive transport?

Answer 2

-it requires metabolic energy (i.e. ATP)
-substances move against a concentration gradient
-carrier proteins are involved as ‘pumps’
-only specific substances are transported

Question 3

What is the process of direct active transport?

Answer 3

-a molecule/ion binds to a carrier protein’s receptor sites on the cell membrane
-on the inside of the cell/organelle, ATP binds to the protein (splitting into ADP and a phosphate molecule). the protein changes shape and opens to the other side of the membrane
-the molecule/ion is released on the other side of the membrane
-ADP is released from the protein, which reverts to its original shape

Question 4

Give one similarity and one difference between active transport and facilitated diffusion.

Answer 4

(e.g.)
similarity- both use transmembrane proteins to transport molecules across a cell membrane
difference- active transport requires metabolic energy to occur