BIOL308 : Updated SQ 12-15.docx
31 Oct 2013
School
Department
Course
Professor
Document Summary
Distinguish between the terms dna repair and recombination . Dna repair re intrinsic mechanisms used by the body to repair faults in dna and prevent mutations dna may not necessarily be repaired to its correct/original form. Recombination is the exchange of genetic material between two dna molecules, causing rearrangement; it increases variability. Some forms of dna repair incorporate recombination, such as when a nick is encountered in dna during replication: list and briefly explain three major causes for mutation in dna. Errors from replication- mistakes made during replication that were not detected and corrected by dnapi/iii proofreading mechanisms. Spontaneous error- depurination: (hydrolysis of n-glycosyl linkage -> abasic site in dna -> loss in nucleotide) , c deamination : c--> u, others incl a -> hypoxanthine (which pairs with c, not t) External factors: external factors: radiation, changes in temperature, mutagens etc. Alkylating chemicals: adds alkyl group to dna. Reactive oxygen species: base pairs with a and c. highly mutagenic.
