  The biological molecules delivered to Earth on the board of meteorites and
comets were called one of the possible causes of the origin of life. Therefore,
our understanding of the routes of formation of biomolecules in space should
shed the light on the possibility of the existence of habitable extrasolar
planets. The large abundance of organic molecules is found in the space regions
with the lowest temperature. Different routes of the organics formation in
these areas were suggested. In this article, we demonstrate that complex
organic molecules same as important biological molecules can be formed due to
the reaction of C atoms with the mantels of molecular ices covering refractory
dust grains present in the interstellar medium (ISM). Having four valence
electrons, C atoms act as glue joining simple non-organic molecules and
converting them into organic matter. The formation of many molecules is
barrierless and thus can happen at low temperature. The barrierless reaction C
+ NH3 + CO -> NH2CHCO attracts particular interest. The product of this
reaction is an isomer of the central residue of a peptide chain and expected to
be efficiently formed in the translucent molecular clouds. The polymerization
of these molecules leads to the formation of proteins that according to some
theories are life's first molecules. Considering a high abundance of atomic
carbon in the ISM, we expect a high efficiency of the formation of a large
variety of different organic molecules, and show why the amount of organic
material formed by condensation of atomic carbon may be underestimated.
