Chapter 15- Mechanisms and Causes Flashcards
Name some spontaneous mutations.
Tautomeric shifts, deamination, depurination, transposons.
Name some induced mutations.
Base analogs, intercalating agents, UV damage, and alkylation.
What is the repair mechanism for tautomeric shifts?
NER
What is the repair mechanism for deamination?
BER
What is the repair mechanism for depurination?
BER
What is the repair mechanism for transposons?
Depends on the outcome of the mutation.
What is the repair mechanism for base analogs?
BER/Mismatch
What is the repair mechanism for intercalating agents?
NER
What is the repair mechanism for UV damage?
NER
What is the repair mechanism for alkylation?
SOS
Explain mismatch repair.
Corrects errors that remain after proofreading.
The mismatched base is recognized and removed
DNA is resynthesized by DNA polymerase.
Recognition of the “correct” bvase is important.
Explain post replication repair.
When DNA replication skips over a lesion and homologous recombination can repair the strands.
Explain SOS repair.
SOS repair inserts bases randomly as a last resort to save the cell. SOS itself is mutagenic, but it may allow the cell to survive.
Explain photoreactivation repair.
non-mammalia
It removes thymine dimers caused by UV light.
Photoreactivation uses blue photon light as an energy source to enzymatically break apart the thymine dimer.
Explain Base Excision Repair (BER).
Recognizes the damaged base by DNA glycosylase
AP endonuclease cuts the phosphodiester bonds.
The DNA is replaced by DNA polymerase and ligase.
