Question

the dopamine molecule is capable of making strong hydrogen bonds. edit the dopamine molecule so that it can no longer make strong hydrogen bonds

Answer 1

Hydrogen bonds occur in the presence of H-N, H-O, and H-F bonds due to the large difference in electronegativity between H and N, O, or F. This means that electrons spend a larger proportion of their time around the N, O, or F nucleus since the electronegativity is so much greater. The result is the development of a dipole in which N, O, or F holds a partial negative charge and H holds a partial positive charge.

Have a look at a molecule of dopamine: http://en.wikipedia.org/wiki/Dopamine You can see there are two H-O bonds and two H-N bonds. You would need to eliminate these to prevent formation of hydrogen bonds (either remove these atoms completely or substitute the H atoms with another, more electronegative element).