Final answer:
The gap left by the removal of an RNA primer during DNA replication is filled by DNA polymerase, which adds dNTPs matching the template strand, and is sealed by DNA ligase forming a phosphodiester bond to maintain a continuous DNA strand.
Step-by-step explanation:
During DNA replication, RNA primers are necessary to initiate the synthesis of the new DNA strands. The leading strand is synthesized continuously in a 5' to 3' direction, requiring only a single RNA primer. In contrast, the lagging strand is synthesized in Okazaki fragments, each starting with its own RNA primer. Once a fragment is synthesized, the primer is removed by exonuclease activity, specifically from the DNA polymerase I enzyme in prokaryotes. This removal leaves a gap in the sugar-phosphate DNA backbone where the primer was.
The next step involves filling these gaps with the appropriate DNA nucleotides. DNA polymerase adds dNTPs (deoxyribonucleoside triphosphates), ensuring that the sequence is accurately replicated according to the template strand. These nucleotides are added in a 5' to 3' direction, matching the original DNA sequence the RNA primer had initiated.
The final step in DNA replication is the sealing of the strand to create a continuous double helix. This is where DNA ligase comes into play. DNA ligase catalyzes the formation of phosphodiester bonds between the adjacent DNA fragments, effectively closing the gaps and ensuring the integrity of the newly synthesized DNA strand. Without these critical steps, DNA replication would be incomplete and the genetic information could not be accurately passed to the next generation of cells.