DNA Mutation And Repair Flashcards
Types of changes
-substitutions
-Insertions
-Deletions
-Expanding nucleotide repeats
Functional effect changes
-Reverse
-Missense
-Neutral
-Nonsense
-Silent
-Suppressor
Base substions
-transitions
-Transversions
Base substitution types
Transitions and Transversions
Transition
Transversions
Frameshift
Number of bases added or removed is not divisible by 3
Insertions
Deletions
Expanding nucleotide repeats
Model of nucleotide repeat expansion
Reverse mutation
Changes the mutant codon back to the original codon
Missense mutation
A base substitution that results in a different amino acid in a protein
Neutral mutation
A type of missense mutation that alters the amino acid sequence but does not significantly change its function
Nonsense mutation
Changes a sense codon into a stop codon (TGA, TAA, TAG)
Silent Mutation
Changes a codon to a synonymous codon that specifies the same amino acid
Suppressor mutation
Suppresses the effect of an earlier mutation at a different site (does not change the sequence back to the original)
Types of DNA damage
-Endogenous
-Environmental
Endogenous DNA damage causes:
-mistakes during DNA replication
-Depurination
-Deamination
-Oxidation ( by endogenous reactive oxygen species)
-non-enzymatic methylation
Environmental damage causes
-Radiation (UV or ionizing)
-environmental chemicals (e.g. DNA methylating agents, chemotherapeutic agents (DNA-cross-linking), bulky hydrocarbons (smoking))
-To function as an information storage molecule, there must be means to repair damaged DNA
Endogenous DNA-DAmaging Reactions
UV damage
Smoking damage
DNA repair processes
DNA types of damage summary
Nucleotide Excision Repair
Base Excision Repair Systems
Basic pathway of DNA repair
Double stranded break
