Respuesta :
Answer:
The correct answer is: on the side of the membrane that has a higher concentration of the cargo molecule immediately after a phosphate has been added to the carrier protein.
Explanation:
- A Carrier protein can be defined as an integral membrane protein that spans across the plasma membrane and is responsible for transporting molecules against the gradient of their concentration.
- A Carrier protein operates in the following manner:
- In the unphosphorylated state, the carrier protein remains open to that side of the plasma membrane which has a low concentration of the solute molecules.
- It binds to ATP (adenosine triphosphate) which causes it to bind to the solute molecules by increasing its affinity towards the solute molecules.
- This is followed by the phosphorylation of the carrier protein with a kinase enzyme using the bound ATP (adenosine triphosphate).
- This causes the carrier protein to have a conformational alteration that makes it open towards that side of the plasma membrane where the concentration of solute molecules is high.
- The phosphorylated form of the carrier protein has a low affinity towards the solute molecules and so it releases the solute molecules in that side of the membrane where the concentration of solute molecules is high.
- The phosphate group from the carrier protein is removed by a phosphatase.
- Now, the de-phosphorylated carrier protein again comes back to its original conformation and faces that side of the plasma membrane where the concentration of solute molecules is low.
