Question

a dna molecule replicates to produce two new dna molecules. both of the two new dna molecules then replicate to form four more new dna molecules. are any nucleotide chains from the original dna present in the last from new dna molecules? if so, how many?

Answer 1

Yes, after two rounds of semiconservative DNA replication, each of the four new DNA molecules will contain one original strand from the initially replicated DNA.

Step-by-step explanation:

During DNA replication, each original DNA strand serves as a template for the synthesis of a new complementary strand, resulting in two identical DNA molecules, each comprising one original (parental) strand and one newly synthesized (daughter) strand. This replication method is known as semiconservative replication. When the original DNA molecule replicates to form two new DNA molecules, and then each of those molecules replicates again, the four resulting DNA molecules will indeed contain nucleotide chains from the original molecule. Specifically, after two rounds of DNA replication, there will be two nucleotide chains from the original DNA present in the last four new DNA molecules, since one original strand is conserved in each of the new DNA molecules after every replication event.