Protein Pumps and Active Transport
ATP hydrolysis
ATP ---> ADP + P
What is used to provide energy in active transport
- ATP is used to provide the energy necessary. It is hydrolysed into ADP. - Potential energy than can be used is stored in the phosphate bonds. When ATP is hydrolysed the phosphate bonds are broken and energy is released to be used to drive cellular reactions.
Active transport is necessary when molecules are being transported against their concentration gradient.
- In this case, diffusion is not possible.
The sodium-potassium pump is an excellent example of protein pumps being used for active transport.
- The integral protein uses ATP to pump 3 sodium ions at a time out of the cell while, at the same time, pumping 2 potassium cells into the cell. - The movements of two different substances at the same time is known as co-transport.
Protein pumps
- They use this energy to pump molecules across the cell membrane, moving from a low concentration to a high concentration. - This energy changes the shape of the protein, allowing it to move molecules through the membrane.