The nuclear genome of a single human cell (i.e., the entire diploid complement)contains about 6.6 billion (6.6 × 10⁹)base pairs of DNA.If synthesis at each replication fork occurs at an average rate of 50 nucleotides per second, all the DNA is replicated in 5 minutes.Assume that replication is initiated simultaneously at all origins.Assuming that the origins are approximately equally distributed across the chromosomes, what is the average number of origins per human chromosome? A)4783 B)19, 130 C)4)6 × 10⁶ D)1)21 × 10⁹ E)2)9 × 10¹⁰

Question

Quizplus · Accepted Answer

The correct answer is A.The total number of nucleotides in the human genome is 6.6 × 10^9. If replication occurs at an average rate of 50 nucleotides per second, then the total time required for replication is 6.6 × 10^9 / 50 = 1.32 × 10^8 seconds. Since replication is initiated simultaneously at all origins, the average number of origins per chromosome is 1.32 × 10^8 / (23 × 60 × 60) = 4783.

The Nuclear Genome of a Single Human Cell (I