Organization, Replication, and Types of DNA in Vivo 319 



34.5. What would you have expected to see in the ultracentrifuge tube following sonic 

 treatment of DNA (p. 315), or following the conversion of DNA to its single-stranded 

 condition (p. 315), if synthesis occurred at the ends of the double DNA helix? 



34.6. What evidence can you give that heating double helix DNA causes the chains to 

 separate? 



34.7. When is DNA single-stranded? 



34.8. A double helix of DNA has a base sequence ATTAGCA on one strand. Can you 

 make an inversion after breaking the backbone at two places on this single strand? 

 Explain. Can you make an inversion if the backbone of the complementary chain is 

 also broken at exactly the same two levels? Explain. 



34.9. Given two double helices whose backbones are broken at the places indicated by 

 periods. 



ATCG.GCAT AT.TAG 



TAGC.CGTA TA.ATC 



Draw the base sequences which may occur following reciprocal translocation between 

 double helices. 



