Cell Membrane Transport

Passive transport, FACILITATED DIFFUSION
In the bloodstream, the oxygen is known to have a very high affinity with hemoglobin molecules on the surfaces of red blood cells.
In the facilitated diffusion of oxygen, the protein hemoglobin act as the carrier that brings it inside the red blood cells.
During this process, the rate of oxygen diffusion is increased by hemoglobin, and after that, the newly-formed oxyhemoglobin will be displaced.

Carrier Proteins:
• Integral glycoproteins which bind a solute and undergo a conformational change to translocate the solute across the membrane
• Carrier proteins will only bind a specific molecule via an attachment similar to an enzyme-substrate interaction
• Carrier proteins may move molecules against concentration gradients in the presence of ATP (i.e. are used in active transport)
• Carrier proteins have a much slower rate of transport than channel proteins (by an order of ~1,000 molecules per second)
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