Flashcards in 2.15 DNA Mutations Deck (20):
Many DNA Polymerase have what type of activity to reduce error?
Exonuclease activity that can go in either direction. This helps Proofread.
What is a nonsense mutation
When a termination codon has been placed in the middle of the gene that results in premature termination
What mutation is a single amino acid replacement in the protein
What is a frameshift mutation
The addition or deletion of one or two base pairs
Describe the DNA damage of Mispairing
One mis-paired base will result in complete change of sequence after multiple replications
What type of DNA damage occurs during the lost of the purine base and therefore the nucleotide
What type of DNA damage occurs when the structure is completely changed to a different base?
What occurs to the DNA during UV damage?
Produces Thymine dimers which are covalent bonds between adjacent pyrimidines particularly Thymine
Name the three strategies of DNA repair
1. Direct Reversal
2. Base Excision Repair
3. Nucleotide Excision Repair
What is the product of the deamination of Adenine
Deamination product of Guanine?
Deamination production of Uracil
Deamination product of Thymine
T or F, A number of carcinogens are mutagenic because they add bulky chemical groups to the DNA which distort the molecule
Describe Direct Reversal
A methylated base can be demethylated by an enzyme that transfer the methyl group to a cysteine residue within its core
Describe Base Excision repair
When a base is damaged through deamination or depurination (etc.), the base is removed as well as the sugar. DNA polymerase adds new nucleotide and DNA ligase seals the hole
Describe Nucleotide excision Repair
A group of nucleotides are excised and repaired by DNA polymerase and DNA ligase
What type of double stranded DNA break repair methods fixes the break WITHOUT losing nucleotides?
Homologous end joining
What occurs during Non-homologous end joint fixing?
The accidental break is cleaned up by Nuclease
Ligase reattaches broken ends
There is a deletion of DNA sequence that was damaged