Question

Each human cell normally contains 23 pairs of chromosomes. Chromosome 1 is the longest and is approximately 247,200,000 basepairs in length.

(A) If there was only one origin of replication, how long (in hours) would it take to replicate Chromosome 1? Remember, the replication rate in eukaryotes is ~75 nucleotides/second

Answer 1

first one need to know the difference between nucleotide and base pair which is Nucleotide is the single unit of a polynucleotide chain. It is composed of a pentose sugar ( ribose in RNA and deoxyribose in DNA ), a nitrogenous base (purine or pyrimidine) and a phosphate group. Whereas a base pair is a pair of a purine and a pyrimidine joined by hydrogen bonds , between two nucleotides.

thus for replication it needs only one strand which would have half of the base pairs given

one strand has nucleotides= 247200000/2= 123,600,000 nucleotides

time would be calculated simply by dividing nucleotides mentioned above by 75

= 123,600,000/75

=1,648,000 seconds= 27,466.6 min =457.7 hour