Real world importance of IM forces: Did you know that hydrogen bonding is critical to the operation of DNA? Hydrogen bonds hold together the two strands of DNA by connecting complementary base pairs, Adenine and Thymine, and Cytosine and Guanine.

a$.$ How many hydrogen bonds exist between each of the following DNA base pairs?

Thymine$-$Adenine $=$

Cystosine$-$Guanine $=$

b$.$ Why is there no dotted line shown between the bottom $O$ and $H$ in the Thymine$-$Adenine base pair?

c$.$ Why is it important for DNA function that hydrogen bonds are not as strong as most covalent $($bonding$)$ forces?