A disposable unit for a biopsy device includes a hollow needle configured to define a longitudinal path. A sample-receiving device having a cavity is configured to move in the hollow needle along the longitudinal path between an extended position and a retracted position. A transport device is configured to move the sample-receiving device in the hollow needle between the extended position and the retracted position. The transport device includes a bendable elongate element having a proximal portion and a distal end, the distal end being connected to the sample-receiving device. The bendable elongate element has a tooth surface that is engaged by a rotatable gear. A coiling device is configured to coil the proximal portion of the bendable elongate element as the sample-receiving device is moved linearly along the longitudinal path from the extended position to the retracted position by operation of the rotatable gear.