Some embodiments include a memory cell having a transistor with a channel region between a first source/drain region and a second source/drain region. A controlled-conductivity region is adjacent the first source/drain region. The controlled-conductivity region has a low-conductivity mode and a high-conductivity mode. The high-conductivity mode has a conductivity at least 106 greater than a conductivity of the low-conductivity mode. The channel region includes a first material having a first bandgap, and the controlled-conductivity region includes a second material having a second bandgap which is greater than the first bandgap. A charge-storage device is electrically coupled to the first source/drain region through the controlled-conductivity region. A bitline is electrically coupled to the second source/drain region.