Alcohol is a poison (for yeast as well as for people) and so the yeast is not able to grow when the alcohol content gets too high. This is why wine is never more than about 12% alcohol.
Ideally the strong nuclear force would say how the protons and neutrons are bonded together, but there is a conceptual chasm in this area. It is unclear how the residual nuclear force (at nucleus level) emerges from the strong force (at quark level), except as a general concept that the gluons leak out.
A chemical bond between the phosphate group of one nucleotide and the sugar of a neighboring nucleotide holds the backbone together. Chemical bonds (hydrogen bonds) between the bases that are across from one another hold the two strands of the double helix together. Bases.