Term
| 3 postulated methods of DNA Replication |
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Definition
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Term
| Meselson-Stahl Experiment |
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Definition
Bacteria were grown in media that contained a heavy isotope of nitrogen. All the DNA in the cells was labeled as "heavy‟. Bacteria were then transferred to unlabeled medium (light) and allowed to grow (replicate). Heavy DNA and light DNA and intermediate DNA could be distinguished by centrifugation (three peaks). After transfer to "light‟ medium, samples were taken at various time points and the density of the DNA was
determined.
Conclusion: Replication is semiconservative |
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Term
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Definition
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Term
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Definition
| DNA Pol need a primer. RNA Pol doesn't. |
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Term
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Definition
replication and repair
catalyzes ~20 cycles at a time
5'-3' polymerase
3'-5' and 5'-3' exonuclease |
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Term
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Definition
| Core that is responsible for replication of the chromosome 3 subunits: α, ε, θ |
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Term
| The chain elongation reaction is carried out by 3'OH ________attack on ___________. |
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Definition
| nucleophilic, a-phosphoryl group on 5' end of DNA |
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Term
| _______ is released as a result of chain elongation. |
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Definition
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Term
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Definition
| how long a polymerase can stay on the template and continue to synthesize DNA |
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Term
| How can E. coli Pol I be cleaved? |
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Definition
| by trypsin or subtilisin b/t residues 323 and 324. This separates 5'-exonuclease domain (i-323) from polymerase/3'exonuclease domain (Klenow fragment) |
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Term
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Definition
| fragment of DNA Pol responsible for polymerase & 3'-exonuclease (I-324) |
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Term
| E. coli DNA Pol III subunits, sizes and responsibilities |
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Definition
α(130kD): Polymerase
β: dimer forms ring/clamp around DNA
γ-complex: clamp loader
ε(27.5kD):3'-exonuclease
θ(8.6kD): ε subunit stabilization
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Term
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Definition
| protect single stranded DNA from exonucleolytic degradation |
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Term
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Definition
Involved in decision to begin replication at the ORIGIN of replication (this
occurs at only one place on the E. coli chromosome) |
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Term
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Definition
| Synthesizes RNA primers required by DNA pol III |
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Term
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Definition
| Joins adjacent DNA chains together |
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Term
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Definition
| Prevents DNA from getting all knotted up as the polymerase moves |
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Term
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Definition
| unwinds strands of DNA so the polymerase can move downstream |
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Term
| Where is primase bound during DNA replication in E. coli? |
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Definition
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Term
| How many total bp in human genome? |
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Definition
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Term
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Definition
G0- hibernation mode
G1- rapid growth
S- DNA synthesis
G2- Cell division Prep
M- Mitosis |
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Term
| Eukaryotic DNA Polymerases |
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Definition
α
δ - principle DNA Pol (associates with PCNA)
ε |
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Term
PCNA (proliferating cell nuclear
antigen) |
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Definition
PCNA is the eukaryotic counterpart of the E. coli β subunit-sliding clamp. This subunit is responsible for
processivity of the polymerase. |
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Term
| 3 other types of polymerases |
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Definition
Telomerase - RNA dependent, telomere synthesis (TTAGGG)
Reverse Transcriptase - used by retroviruses RNA->DNA -> integration into host's chromosome for replication (tRNA is primer), low fidelity, blocked by drug AZT in HIV patients
Taq - PCR, thermostable even at 95 degrees |
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Term
| 3 enzymatic activities of Reverse Transcriptase |
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Definition
1) RNA-directed DNA polymerase activity
2) RNase H activity (an exonuclease activity that degrades RNA chains
in DNA:RNA hybrids)
3) DNA-directed DNA polymerase activity which replicates the ssDNA remaining after RNase H degradation of the viral genome. |
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Term
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Definition
| recombination model: proposes a series of steps like synapsis, strand invasion, branch migration, and resolution |
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Term
| Meselson and Weigle's experiment |
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Definition
Density-labeled “heavy” phage
(ABC) was used to coinfect
bacteria along with “light” abc
phage.
The progeny included recombinant
phage – ABc, Abc, aBc, aBC, and
so on, distributed diffusely
between the two parental bands
(ABC and abc).
Conclusions: Recombination occured |
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Term
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Definition
| initiates recombination in E. coli |
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Term
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Definition
| binds single-stranded DNA, forming a nucleoprotein filament capable of strand invasion and homologous pairing in E. coli |
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Term
| RuvA, RuvB, and RuvC proteins |
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Definition
| drive branch migration and process the Holliday junction into recombinant products in E. coli |
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Term
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Definition
| a site-specific DNA nuclease essential for transposition |
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Term
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Definition
(a) creating a staggered cut
(b) whose protruding ends are ligated to
the transposon
(c) Gaps are filled in and ligated
(d) transposon insertion thus generates direct repeats in the host DNA. |
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Term
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Definition
| Animals that have acquired new genetic information as a consequence of introduction of foreign genes |
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