Term
| What are the 3 theoretical models of DNA replication? |
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Definition
| semiconservative, conservative, dispersive |
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Term
| Which experiment discovered the model for DNA replication? How did it work? |
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Definition
| Meselson-Stahl experiment, tagged DNA with heavy and light nitrogens and then saw where the bands appeared when centrifugation happened. |
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Term
| What would be the result of the Meselson-Stahl experiment if DNA was not semiconservative? |
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Definition
| If conservative, 2 bands would appear starting in the first tube, concentration of heavier band would slowly be lessened compared to the lighter band. For dispersive, there would be a single band always that would gradually get lighter and lighter until it got close to the area of the 14N band. |
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Term
| When does DNA replication occur? |
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Definition
| During S phase only, and only once per cell cycle. regulated by cyclin dependent kinase |
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Term
| Where does replication begin on a chromosome? are there more than one of these sites? |
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Definition
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Term
| What is the difference between the leading and lagging strand? |
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Definition
| leading strand always codes away from origin of replication, is continuous. lagging strand needs to leapfrog and moves towards the replication origin, creates okazaki fragments |
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Term
| In what direction are all new DNA strands formed? |
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Definition
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Term
| What is the complete complement of replication fork proteins called? |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| ssDNA binding proteins (RPA) do what? |
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Definition
| prevent the closing of the dsDNA |
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Term
| What protein seals the nicks in the okazaki fragments? |
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Definition
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Term
| How long are RNA primers approximately? |
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Definition
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Term
| What is the DNA polymerase replication error rate in humans? What is the replication rate after the proofreading mechanism? |
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Definition
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Term
| What are some types of DNA damage? |
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Definition
| Alkylation of G base, deamination of C to make U (caused by bacon and nitrates), removal of base, mismatch, pyrimidine dimer (2 Ts that bind due to UV radiation), ss breaks and ds breaks |
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Term
| What are the 3 main categories of DNA repair mechanisms? |
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Definition
template independant damage
pyrimidine dimers: photoreactivation by photolyase
methylated guanine: reversed by MGMT
ssDNA damage repair
base excision repair
nucleotide excision repair
mismatch repair
DSDNA breaks
homologous recombination
non-homologous end joining |
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Term
| What are some sources of double stranded breaks? |
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Definition
| crossing over, ionizing radiation, DNA replication errors (replication fork stress) |
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Term
| What is ataxia telangiectasia? What causes it? What defect contributes to it? |
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Definition
| gamma irradiation, failure to repair double strand breaks |
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Term
| What causes bloom syndrome? What DNA repair defect contributes? |
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Definition
| mild alkylating agent; replication stress response |
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Term
| What causes cockayne syndrome? What DNA repair defect contributes? |
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Definition
| UV light; failure of nucleotide excision repair to function properly |
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Term
| What causes fanconi anemia? What DNA repair defect contributes? |
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Definition
| cross-linking agents; replication stress response |
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Term
| What causes xeroderma pigmentosum? What DNA repair defect contributes? |
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Definition
| UV light, chemical mutagens; failure of nucleotide excision repair to work properly |
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Term
| What DNA repair defect contributes to Hereditary nonpolyposis colorectal cancer? |
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Definition
| Inability of mismatch repair to function properly |
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