Disrupting a biological cell includes freezing, boiling or perhaps alternately freezing and boiling material containing the biological cell using a thermoelectric cell with a working face, and a base face whereof is contiguous with a heat source/sink at a substantially constant temperature. Apparatus for the disruption process includes a peltier cell, a base face, which is flexibly attached to a heat source/sink held at a constant temperature, and a working face contiguous with a reaction vessel or holder thereof. Reversal of the voltage in the peltier cell enables the working face alternately to reach below freezing and above boiling temperatures, and/or with use of a resistive wire on the vessel or holder for heating, with the TEC used purely for cooling. The materials of the base face tend to inhibit disintegration of the peltier cell brought about by expansion and contraction by heat.