Flashcards in DNA Replication/Repair 2 Deck (15):
What are DNA gyrases (Topoisomerases ) for?
They nick DNA to loosen (negative supercoil) DNA strands
It’s necessary for Helicase to do its job
Fluoroquinolones inhibit the following enzymes in prokaryotes ?
1. Topoisomerases II and IV
In Eukaryotes, Topoisomerase I is inhabited by the following agents?
In Eukaryotes, Topoisomerase II is inhabited by the following agents?
How is the Telomere involved in cellular aging ?
1. It’s the end portion of the chromosomes
2. Has repetitive sequences
3. DNA polymerase can’t keep up with synthesis
4. Telomere gets shorter
5. Cell dies
6. Prevented by telomerase activity
What is Telomerase for?
1. Aids in DNA synthesis of the Telomeres
2. It’s a reverse transcriptase (RNA dependent DNA polymerase )
2. Goes haywire with tumors
What is reverse transcriptase ?
1. Synthesizes DNA from RNA (reverse).
2. Present in many viruses in order to add their genome into the host’s
3. Inhibited by AZT
What is the main cause of Thymine dimers?
Enzyme necessary to remove Thymine Dimers?
1. Excision endonuclease
Tumor suppression genes that regular G1 entry into S phase ?
What happens in cytosine deamination?
1. Cytosine looses amino group—>
Excision enzyme for Cytosine deamination ?
Uracil Glycosylase Endonuclease
Enzyme absent in Xeroderma pigmentosum ?
Damage to this DNA repair mechanism causes Lynch Syndrome ?
DNA mismatch repair