Biomes are areas of a planet with varying properties like compound rates and environment values (temperatures, sunlight intensity and other global variables).
Patches are regions which divide a planet. Each patch has a biome assigned into them, but there may be more than one patch with a common biome. Currently, they are predetermined, but it's planned that they are going to be procedurally generated. In the Microbe Stage the player can only change between patches in the Patch Map in the editor.