As in traditional computers, future bio-computers might feature the analogous mechanism to carry out a set of arithmetic or logical operations sequentially. In digital computers, memory is essential for which digitised information is encoded, stored, and retrieved. A stored memory unit in the computer is almost constructed by metal–oxide–semiconductor field-effect transistors. In the future, realising the specific data stored memory unit in the biocomputer is essential. However, it is not easy to realise that mechanism for data memorisation in biological systems. The authors propose a structure of a fundamental memory unit necessary with input/output configuration for data read and write for the biocomputer.