1. You should have found two mismatches in the RNA hairpin: an A:G mismatch and a C:C mismatch. Most people got this right. I few people didn't notice the C:C mismatch.

2. In DNA, T (thymine) will base-pair with adenine making two hydrogen bonds. Nearly eveyone got this right.

3. The two differences in the sequences are I/R and H/S. Of the two substitutions, I/R is less conservative because I (isoleucine) is a nonpolar amino acid typically found on the protein interior and R (aRginine) is a very polar amino acid that is positively charged (basic). Assuming this alignment is correct, the mutated position is probably on the exterior of the protein. The H/S substitution is more conservative because both amino acids are polar. There is a considerable size difference, however. S (serine) is small while H (histidine) is large and also positively-charged (basic).

4. Surprisingly, a lot of people missed the next question despite my explicit warning that the quiz would be on amino acid one letter codes. If you had trouble here, go back and learn the codes.

glutamic acid E polar, negatively-charged (acidic)
glutamine Q ("Qtamine") polar. Looks a lot like E but is not charged.
tyrosine Y (tYrosine) aromatic, mostly nonpolar but has an -OH group so can make hydrogen bonds.
threonine T polar, small, beta-branched
leucine L nonpolar, medium-sized
lysine K positively-charged (basic), polar due to charge but has a long nonpolar chain preceding the +-charged amino group.