MICR 271 FINAL EXAM QUESTIONS AND ANSWERS

MICR 271 FINAL EXAM QUESTIONS AND ANSWERS
Replisome Speed - CORRECT ANSWER✅✅eukaryotic slower - must displace nucleosomes, cell-
dependent regulation of replication



multiple initiation sites to compensate



Bacterial Replication Forks - CORRECT ANSWER✅✅1. Helicase unwinds DNA, lagging strand coated with
single stranded binding proteins, RNA primer synthesized by primase



2. DNA Pol III holoenzyme tethered to DNA by beta clamp, loaded by t-clamp loader



3. 1 Pol III core leading strand synthesis (continuous)



4. 2 Pol III cores lagging strand synthesis (okazaki fragments)



5. Pol I removes primer and fills with DNA, Ligase joins strands



Eukaryotic Replication Fork - CORRECT ANSWER✅✅1. Helicase (Mcm2-7) + proteins (GINSS, Cdc45,
Mcm10) activate unwound DNA, ssDNA bound by replication protein A



2. Helicase associates wtih primase (synthesizes RNA primer)



3. Pol ε does leading, Pol δ does lagging (loaded onto DNA by proliferating cell nuclear antigen, carried
to DNA by replication factor C)



4. shorter okazaki fragments generation, Pol δ removes RNA primer and fills with DNA, ligase seals gap



Family A DNA Polymerases - CORRECT ANSWER✅✅replication/repair

,Family B DNA Polymerases - CORRECT ANSWER✅✅DNA replication, 3'-5' exonuclease activity



Family C DNA Polymerases - CORRECT ANSWER✅✅DNA replication



Family D DNA Polymerases - CORRECT ANSWER✅✅DNA replication



Family X DNA Polymerases - CORRECT ANSWER✅✅DNA damage repair



Family Y DNA Polymerases - CORRECT ANSWER✅✅translesion DNA repair



Translesion Repair - CORRECT ANSWER✅✅insert bases opposite damaged nucleotides or repair dsDNA
breaks



Class I virus - CORRECT ANSWER✅✅dsDNA genome



mRNA synthesis: transcription using host machinery, translatin mRNA --> proteins



genome replication: using host machinery



Class II virus - CORRECT ANSWER✅✅ssDNA genome (+ or -)



mRNA synthesis: dsDNA transcribed into mRNA using host machinery



genome replication: dsDNA produced and replicated, strands separated



Class III virus - CORRECT ANSWER✅✅dsRNA genome



mRNA synthesis: separated into ssRNA, + strand used as mRNA, translated into viral proteins

, genome replication: + ssRNA = template to produce new dsRNA



Class IV virus - CORRECT ANSWER✅✅+ ssRNA genome



mRNA synthesis: + ssRNA used as mRNA, translated into proteins



genome replication: + ssRNA used to produce - ssRNA = template to produce new + ssRNA



Class V virus - CORRECT ANSWER✅✅- ssRNA genome



mRNA synthesis: -ssRNA template to make + ssRNA (mRNA) translated into proteins



genome replication: -ssRNA used to produce + ssRNA = template to produce new -ssRNA



Class VI viruses - CORRECT ANSWER✅✅Retroviruses



ssDNA reverse transcribed from RNA genome, dsDNA made using DNA Pol



mRNA synthesis: dsDNA integrated into host genome --> mRNA --> protein



genome replication: + ssRNA --> ssDNA by viral reverse transcriptase --> dsDNA into host genome by
integrase --> +ssRNA to produce new genomes



Class VII viruses - CORRECT ANSWER✅✅Reverse transcribing dsDNA genome



mRNA synthesis: dsDNA --> mRNA by viral RNA Pol --> proteins



genome replication: + ssRNA --> ssDNA by reverse transcriptase --> partially dsDNA genomes