Micro cuvette assembly for examining biological samples has a first partial plate with one or more first cuvette surfaces and a second partial plate opposite the first and which also has one or more second cuvette surfaces. In an active position of the assembly, the second cuvette surfaces are arranged parallel and in register with the first cuvette surfaces and are spaced apart from the first cuvette surfaces whereby one or more micro cuvettes are formed. The first and second partial plates also have openings arranged in register with the cuvette surfaces and transparent bodies are provided as the cuvette surfaces. The first and second plates are completely penetrated by these openings and the transparent bodies are manufactured from a different material than the partial plates and span the openings close to a first surface of the partial plates. The first and second cuvette surfaces of a micro cuvette in the active position are wetted by a liquid volume which has previously been applied to one of the cuvette surfaces so that the liquid volume is held between these two cuvette surfaces.