Annual Review of Biochemistry - Essay Example

Although, more often the size of the solute particles is larger than what can easily cross the biomembranes. In that case, there are carrier proteins that bind with the solute and transport them across the membrane. This is known as facilitated diffusion. In facilitated diffusion, the carrier proteins are embedded in the membrane. They bind with the biomolecules and change their shape which results in translocation of the molecules to the other side of the membrane.In a biochemical system, there is frequently need of transporting biomolecules across a membrane against the concentration gradient.

It can be thought of as uphill movement of molecules and it requires energy. The energy used can be chemical in nature as from ATP in various protein pumps or electrochemical due to the difference of electrochemical potential across the membrane. As illustrated by Jack H. Kaplan (2002), an example of active transport pump is Sodium/ Potassium ATPase that uses energy from ATP breakdown to transport ions across membranes.