Hi Moiz,

3) Complementary base pairing is not the method in which DNA breaks are restored. Another way of thinking of it is during DNA replication we are not adding nucleotides to each other with hydrogen bonding but phosphodiester bonds. Hydrogen bonding happens between strands.

19) From Figure 2, when ANS (which binds to hydrophobic residues) was added with protein X, we see ANS fluorescence similar to just ANS alone. This indicates that ANS was not able to bind to any of the surface AA of protein X, suggesting its hydrophilic. The reason why we see an increase in fluorescence upon adding DPC is because DPC, a detergent, breaks tertiary/secondary structure, revealing the hydrophobic residues for ANS to bind.

Hope this helps!