MICR 271 Final Exam Questions with Correct
Answers
Replisome Speed
eukaryotic slower - must displace nucleosomes, cell-dependent regulation of replication
multiple initiation sites to compensate
Bacterial Replication Forks
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
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
replication/repair
Family B DNA Polymerases
DNA replication, 3'-5' exonuclease activity
Family C DNA Polymerases
DNA replication
Family D DNA Polymerases
DNA replication
Family X DNA Polymerases
DNA damage repair
Family Y DNA Polymerases
translesion DNA repair
Translesion Repair
insert bases opposite damaged nucleotides or repair dsDNA breaks
Class I virus
,dsDNA genome
mRNA synthesis: transcription using host machinery, translatin mRNA --> proteins
genome replication: using host machinery
Class II virus
ssDNA genome (+ or -)
mRNA synthesis: dsDNA transcribed into mRNA using host machinery
genome replication: dsDNA produced and replicated, strands separated
Class III virus
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
+ 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
- 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
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
Reverse transcribing dsDNA genome
mRNA synthesis: dsDNA --> mRNA by viral RNA Pol --> proteins
genome replication: + ssRNA --> ssDNA by reverse transcriptase --> partially dsDNA
genomes
T4 Phage
Answers
Replisome Speed
eukaryotic slower - must displace nucleosomes, cell-dependent regulation of replication
multiple initiation sites to compensate
Bacterial Replication Forks
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
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
replication/repair
Family B DNA Polymerases
DNA replication, 3'-5' exonuclease activity
Family C DNA Polymerases
DNA replication
Family D DNA Polymerases
DNA replication
Family X DNA Polymerases
DNA damage repair
Family Y DNA Polymerases
translesion DNA repair
Translesion Repair
insert bases opposite damaged nucleotides or repair dsDNA breaks
Class I virus
,dsDNA genome
mRNA synthesis: transcription using host machinery, translatin mRNA --> proteins
genome replication: using host machinery
Class II virus
ssDNA genome (+ or -)
mRNA synthesis: dsDNA transcribed into mRNA using host machinery
genome replication: dsDNA produced and replicated, strands separated
Class III virus
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
+ 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
- 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
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
Reverse transcribing dsDNA genome
mRNA synthesis: dsDNA --> mRNA by viral RNA Pol --> proteins
genome replication: + ssRNA --> ssDNA by reverse transcriptase --> partially dsDNA
genomes
T4 Phage
