Flashcards in Biochemistry: Genetic material Deck (23)
Enzyme in DNA synthesis that allows uncoiling of supercoiled strand:
One drug that inhibits topoisomerase in prokaryotes? Eukaryotes?
Fluoroquinolones = prokaryotic inhibitor
Etoposide = eukaryotic inhibitor (anti-CA drug)
Direction in which DNA is synthesized:
5' -> 3'
This Ab is made against topoisomerase. What is the disease it is associated with?
Anti-Scl-70 = Ab vs. topoisomerase
Two proteins make up the primeosome for DNA synthesis:
There are four eukaryotic DNA polymerases:
a, d, b, g
How do thymine-thymine dimers happen?
Usually UV light damage.
Thymine - thymine is paired on the same DNA strand.
This DNA repair mechanism repairs bulky helix-distorting lesions:
Name one disease associated with a defect in this repair mechanism:
Nucleotide excision repair.
This DNA repair mechanism is important in repair of spontaneous deamination:
Base excision repair.
This disease results from a defect in DNA helicase specifically. Name three features:
Leukemias / lymphomas
Cancer by age 25 on average
Sensitivity to sunlight
What is the DNA repair defect in xeroderma pigmentosum? Three features of the disease:
Defect in nucleotide excision repair
Absolutely no sunlight, ever
Melanomas and other cancers
This DNA repair mechanism is defective in HNPCC:
What is the DNA repair defect associated with ataxia telangiectazia?
Defect in ds break repair / non-homologous end joining.
In ataxia telangiectasia, what is the first physical sign? Possible laboratory abnormality one might see after 8mos? At what age would you see telangiectasias?
Ataxia / difficulty with smooth visual pursuit, may fail to develop social smile
Elevated AFP possibly around 8 months
Telangiectasias not until age 5
What is the immune deficiency associated with ataxia telangectasia (2 components)?
Decreased numbers of T lymphocytes
Children with this disease are very sensitive to ionizing radiation in particular:
What is the DNA repair defect associated with BRCA1 and BRCA2?
dsDNA repair / non-homologous end joining
The strand of DNA nucleotides that opposes this DNA strand:
5' ATTGCGTA 3'
Remember to write it 5' to 3'
3' to 5' would be TAACGCAT, so the answer is
5' TACGCAAT 3'
Main way in which UV light damages DNA:
Forms thymine-thymine dimers and the same strand of DNA
The eukaryotic DNA polymerase responsible for replicating the lagging strand of DNA:
DNA polymerase alpha
The eukaryotic DNA polymerase responsible for replicating the leading strand of DNA:
DNA polymerase Delta
makes leaDing strand
The eukaryotic DNA polymerase responsible for replicating mitochondrial DNA:
DNA polymerase gamma
The eukaryotic DNA polymerase responsible for repairing DNA:
DNA polymerase beta