Te E. coli chromosome is 1.28 mm long. Under optimal conditions, the chromosome is replicated in 40 minutes.
(a) What is the distance traversed by one replication fork in 1 minute?
(b) If replicating DNA is in the B form (10.4 base pairs per turn), how many nucleotides are incorporated in 1 minute in one replication fork?
(c) If cultured human cells (such as HeLa cells) replicate 1.2 m of DNA during a five hour S phase and at a rate of fork movement one-tenth of that seen in E. coli, how many origins of replication must the cells contain?
(d) What is the average distance, in kilobase pairs, between these origins?