Final answer:
The processes that involve making phosphodiester bonds include DNA replication, telomere synthesis, transcription, and reverse transcription. Breaking phosphodiester bonds occurs during RNA splicing, DNA repair, and the proofreading stage of DNA replication. These processes are pivotal in maintaining genetic code integrity and expression.
Step-by-step explanation:
The question specifically asks about the processes that involve making and breaking of phosphodiester bonds, which are the bonds connecting the nucleotides in polynucleotides like DNA and RNA. These bonds are critical for the integrity and function of genetic material, and several biological processes are involved with the phosphodiester bonds.
Processes Making Phosphodiester Bonds
DNA Replication: DNA polymerases catalyze the formation of phosphodiester bonds between the hydroxyl group of the 3'-end of the growing strand and the incoming nucleotide which is complementary to the template strand.
Telomere Synthesis: The enzyme telomerase extends the ends of chromosomes, allowing DNA polymerase to complete synthesis.
Transcription: RNA polymerase catalyzes the formation of phosphodiester bonds during the synthesis of RNA from a DNA template.
Reverse Transcription: The enzyme reverse transcriptase synthesizes DNA from an RNA template, forming phosphodiester bonds.
Processes Breaking Phosphodiester Bonds
RNA Splicing: Introns are removed and exons are reconnected, involving the breaking and reformation of phosphodiester bonds.
DNA Repair: During repair processes, incorrect or damaged nucleotides are excised and the gaps are sealed with new phosphodiester bonds.
Proofreading (during replication): Wrongly incorporated nucleotides are excised by the 3' exonuclease activity of DNA polymerase, which breaks the phosphodiester bond that had incorporated the incorrect nucleotide.
Overall, the formation of phosphodiester bonds is critical to the maintenance and expression of the genetic code, while their controlled cleavage is essential for correcting errors and modifying RNA molecules after their synthesis.