Chapter 12, Problem 20P

The mitotic cell divisions in the early embryo of D. melanogaster occur very rapidly (every eight minutes).

a.	If there were one bidirectional origin in the middle of each chromosome, how many nucleotides would DNA polymerase have to add per second to replicate all the DNA in the longest chromosome (66 Mb) during the eight-minute early embryonic cell cycles? (Assume that replication occurs during the entire cell division cycle.)
b.	In fact, many origins of replication are active on each chromosome during the early embryonic divisions and are spaced approximately 7 kb apart. Calculate the average rate (per second) with which DNA polymerase adds complementary nucleotides to a growing chain in the early Drosophila embryo, making the same assumption as in part (a).