Overview Function replicate cell genome in a manner that is highly accurate Process DNA melted to expose single strand to expose origin of replication single stranded binding proteins (SSBs) bind and stabilize melted DNA RNA primer added in 5' → 3' direction by primase DNA polymerase adds adds nucleotides in a 5' → 3' DNA polymerase III in prokaryotes DNA polymerase α and δ in eukaryotes can edit mistakes with a 3' → 5' exonuclease activity adds continuously on the leading strand adds discontinuous Okazaki fragments on the lagging strand because it must synthesize in a 5' → 3' direction DNA gyrase (topoisomerase II) breaks the DNA to prevent coiling RNA primer removed by RNAase H in eukaryotes and filled by a DNA polymerase by DNA polymerase I in prokaryotes and can fill simultaneously DNA ligase seals the nick between fragments Differences between prokaryotes eukaryotes prokaryotes single origin of replication eukaryotes multiple origins of replication Clinical importance antibiotics quinolones, fluoroquinolones block bacterial topoisomerase used to treat aerobic gram negatives in UTIs and gonorrhea e.g. drugs ending in -floxacin cancer chemotherapy etoposide, teniposide block eukaryotic topoisomerase
QUESTIONS 1 of 5 1 2 3 4 5 Previous Next (M1.BC.17.4707) A 55-year-old male with a 60 pack-year smoking history presents to his oncologist for ongoing management of his recently diagnosed small cell lung cancer. His oncologist discusses several options and decides to start the chemotherapeutic medication, etoposide. The patient is warned that one side effect of this drug is myelosuppression so he should be vigilant for development of any infectious symptoms. The beneficial effect of this drug in treating cancer is most likely due to which of the following effects? QID: 108444 Type & Select Correct Answer 1 Alkylation of DNA 15% (53/347) 2 Crosslinking of DNA 13% (45/347) 3 DNA intercalation 11% (38/347) 4 Inhibition of supercoil relaxation 49% (171/347) 5 Stabilization of microtubules 8% (29/347) M 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (M1.BC.15.73) A mutant stem cell was created by using an inducible RNAi system, such that when doxycycline is added, the siRNA targeting DNA helicase is expressed, effectively knocking down the gene for DNA helicase. Which of the following will occur during DNA replication? QID: 106556 Type & Select Correct Answer 1 DNA is not unwound 79% (260/329) 2 DNA supercoiling is not relieved 9% (31/329) 3 The two melted DNA strands reanneal 4% (13/329) 4 The RNA primer is not created 1% (4/329) 5 Newly synthesized DNA fragments are not ligated 4% (14/329) M 1 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.BC.13.11) Although nucleotide addition during DNA replication in prokaryotes proceeds approximately 20-times faster than in eukaryotes, why can much larger amounts of DNA be replicated in eukaryotes in a time-effective manner? QID: 100076 Type & Select Correct Answer 1 Eukaryotes have less genetic material to transcribe 1% (1/150) 2 Eukaryotes have fewer polymerase types 2% (3/150) 3 Eukaryotes have helicase which can more easily unwind DNA strands 4% (6/150) 4 Eukaryotes have multiple origins of replication 93% (140/150) 5 Eukaryotes do not have exons 0% (0/150) M 1 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
All Videos (0) Biochemistry | DNA Replication Biochemistry - DNA Replication Listen Now 11:10 min 12/8/2021 59 plays 3.0 (1)