Final answer:
The enzyme that replaces RNA nucleotides with DNA nucleotides after primer removal is DNA polymerase I, followed by DNA ligase which seals the nicks to complete the DNA strand.
Step-by-step explanation:
The enzyme that fills the sequence gaps after primers are removed from a newly synthesized DNA strand is DNA polymerase I, which replaces the RNA nucleotides with DNA nucleotides. Subsequently, DNA ligase is the enzyme responsible for sealing the nicks between the DNA fragments, creating an intact phosphodiester backbone of the DNA molecule.
During DNA replication in prokaryotes, primer sequences composed of RNA nucleotides are laid down to initiate synthesis. These primers are later removed. Following removal, DNA polymerase I fills in these areas with the correct DNA nucleotides, replacing the RNA. Once the gaps left by RNA primers are filled with DNA, DNA ligase comes into action. It catalyzes the formation of a phosphodiester bond between adjacent DNA Okazaki fragments on the lagging strand as well as any other nicks present after replication and repair. In closing these nicks, DNA ligase ensures the continuity and stability of the newly synthesized DNA strand, playing a crucial role in DNA replication and repair processes.