Double-stranded DNA can be unwound (denatured)
by applying heat to break the
hydrogen bonds holding the bases together.
The denatured DNA exhibits stronger UV absorption,
showing a hyperchromic shift during "melting".
- Q: Which sample of DNA in the diagram has a greater percent of GC pairs?
- A: The green sample with the higher melting temperature (Tm).
The Tm increases as GC content increases, since
pairs have 3
hydrogen bonds while
pairs have 2