you are working in a biology lab during your summer break. your supervisor asks you to perform an experiment to find the effective spring constant (in n/m) of a partial molecule of dna (deoxyribonucleic acid). you perform experiments and find that a single straight portion of a dna molecule is 2.11 µm long. you then perform an activity that charges the ends of the molecule; each end becomes singly ionized: negative on one end, positive on the other. after the ends are charged, the molecule shrinks by 1.22% of its length.