This process is called passive transport or facilitated diffusion, and does not require energy. The solute can move "uphill," from regions of lower to higher concentration. This process is called active transport, and requires some form of chemical energy.
It can't really be codominant since lowercase letters are recessive, and condomance needs 2 dominant alleles of a different types. So really it should be BB for blue, RR for red and BR for patchwork...
