ACTIVE TRANSPORT

Question 1

definition of active transport

Answer 1

the movement of molecules / ions from an area of low concentration to high concentration using ATP and carrier proteins against a concentration gradient
highly selective

Question 2

describe the process of active transport

Answer 2

1. molecule binds to receptors on its specific carrier protein
2. ATP binds to the protein on the inside of the cell
3. ATP broken down by hydrolysis into ADP and phosphate causing the carrier protein to change shape
4. carrier protein releases molecule / ion onto other side of membrane
5. phosphate and ADP released from protein causes it to return to original configuration
6. phosphate and ADP combine to make ADP during respiration

Question 3

what is ATP hydrolase

Answer 3

causes chemical energy that has been stored in high energy bonds in ATP to be released by using water

Question 4

describe the sodium potassium pump

Answer 4

1. Na ions are actively transported out through a
   Sodium-Potassium pump from epithelial cell into
   blood (K ions actively transported in).
2. There is now a higher concentration of Na ions in the
   lumen of the intestine than inside the epithelial cell.
3. This causes Na ions to diffuse (down the
   concentration gradient) via a co-transport protein
   into the epithelial cell.
4. As this happens, they carry a glucose / amino acid
   molecule. The glucose / aa is moving against the
   concentration gradient.
5. The glucose / aa is brought into the blood by sodium
   via facilitated diffusion through a carrier protein.

Question 5

what drives the transport of glucose against its concentration gradient

Answer 5

the Na+ ion conc gradient