We studied fluctuations of an optically trapped bead connected to a single DNA molecule anchored between the
bead and a cover glass or between two optically trapped beads. Power spectral densities of the bead position for
different extensions of the molecule were compared with the power spectral density of the position fluctuations of
the same bead without the molecule attached. Experiments showed that the fluctuations of the DNA molecule
extended up to 80% by a force of 3 pN include the colored noise contribution with spectral dependence 1/fα
with α~ 0.75.