  The fundamental processes by which nuclear energy is generated in the Sun
have been known for many years. However, continuous progress in areas such as
neutrino experiments, stellar spectroscopy and helioseismic data and techniques
requires ever more accurate and precise determination of nuclear reaction cross
sections, a fundamental physical input for solar models. In this work, we
review the current status of (standard) solar models and present a detailed
discussion on the relevance of nuclear reactions for detailed predictions of
solar properties. In addition, we also provide an analytical model that helps
understanding the relation between nuclear cross sections, neutrino fluxes and
the possibility they offer for determining physical characteristics of the
solar interior. The latter is of particular relevance in the context of the
conundrum posed by the solar composition, the solar abundance problem, and in
the light of the first ever direct detection of solar CN neutrinos recently
obtained by the Borexino collaboration. Finally, we present a short list of
wishes about the precision with which nuclear reaction rates should be
determined to allow for further progress in our understanding of the Sun.
