Scientists investigated the transport of L-sorbose (a polar hexose sugar) into human red blood cells. The concentration of L-sorbose was 15 mmol dm^-3 in the extracellular fluid and 3 mmol dm^-3 inside the cells.

The rate of L-sorbose transport was measured under different conditions, with the following findings:

• The addition of cyanide (a respiratory inhibitor) did not alter the rate of transport.
• The addition of a chemical that binds to and blocks membrane carrier proteins significantly reduced the rate of transport.

Which process is responsible for the transport of L-sorbose into these red blood cells?