Chapter 16, Problem 16.3PS

DNA Structure. Carefully inspect the double-stranded DNA molecule shown here, and notice that it has twofold rotational symmetry:

$\begin{array}{l}{3}^{\prime }\text{A}-\text{G}-\text{C}-\text{G}-\text{C}-\text{T}-\text{A}-\text{T}-\text{T}-\text{G}-\text{C}-\text{G}-\text{C}-\text{T}{5}^{\prime }\\ {\text{5}}^{\prime }\text{T}-\text{C}-\text{G}-\text{C}-\text{G}-\text{A}-\text{T}-\text{A}-\text{T}-\text{C}-\text{G}-\text{C}-\text{G}-\text{A}{3}^{\prime }\end{array}$

Label each of the following statements as T if true or F if false.

1. (a) There is no way to distinguish the right end of the double helix from the left end.
2. (b) If a solution of these molecules were heated to denature them, every single-stranded molecule in the solution would be capable of hybridizing with every other molecule.
3. (c) If the molecule were cut at its midpoint into two halves, it would be possible to distinguish the left half from the right half.
4. (d) If the two single strands were separated from each other, it would not be possible to distinguish one strand from the other.
5. (e) In a single strand from this molecule, it would be impossible to determine which is the 3′ end and which is the 5″ end.