DNA Structure Activity

Problem 7: Are the two strands of DNA parallel or anti-parallel?

Are the two strands of DNA parallel or anti-parallel? Switch to the view labeled "Antiparallel DNA strands". Only the sugar rings of each base pair are shown. The sugar carbon atoms are colored blue and yellow. Notice that directly opposite each blue sugar on one strand is a yellow sugar on the other strand. Notice that the different colored sugar rings make two helical spirals that wrap around a common axis. The "+" and "-" zoom tools from the Toolbar can be used for zooming in and out. Using the red oxygen atoms as a reference, determine if the two strands of DNA spiral in the:

A.	same direction. The strands are "parallel".
B.	opposite direction. The strands are "antiparallel".