Chapter 12 - Gene Mutation, DNA Repair and Homologous Recombination Flashcards
(35 cards)
What is spontaneous mutations?
Something that happend all of the sudden
What is induced mutation?
Mutations that are caused by mutagens
What is mobile genetics elements?
They are selfish genetic elements that can make copies of themselves throughout the genome.
The fluctation test
A test whether mutation were random in respect to their effects or if adaptive mutations occur when the environement changes
Point mutations
mutations that map to a single and specific point (usually a single base pair or a few base pairs)
What is transitions and tranversions and what are their differences?
Transitions - purine to purine or pyrimidine to pyrimidine.
A <–> C or C <–> T
Transversions - purine to pyraimine or pyrimidine to a purine
A <–> C or A <–>T
G <–> C or G <–> T
What are indels?
They are insertions or deletions
Does not alter the amino acid sequence
Synonymous or Nonsynonymous?
Synonymous
Name a type of synonymous mutation.
Silent mutation
Leads to changes in the amino acid sequence.
Synonymous or Nonsynonymous
Nonsynonymous
Name 3 types of mutation for nonsynonymous mutation.
Missense - leads to a change in the amino acid sequence
Nonsense - stops polypeptide early
Frameshift - Insertion/deletion of single pair
If we have a point mutation in noncoding sequence in the regulatory site such as a promoter what could happen?
That can impact the ability of regulatory protein such as transcription factors to bind at that gene and transcribe.
Cryptic Splice Site
Cryptic splice sites can act as decoy sites for spliceosome selection. They can also introduce frameshifts or stop codons, among other changes in the resulting mRNA.
e.g cutting intron 1 halfway thinking its the end then beginning exon 2
Forward mutation
Something that changes the base pair and alters the polypeptide sequence into a different amino acid.
Reverse mutation
Restores the ability of the gene to produce a functional protein
Which is more common: forward mutation or reversions?
Forward
mutations a random and there’s a lot of ways mutations can occur, hence why forward mutation is more common.
Which gender produces more mutations and why?
Males are the ones who constantly produces mutations because sperm is constantly getting reproduced whereas females dont go through replications like male does.
Bases have natural alternative forms called …
tautomers
(a compound that can switch between different arrangements of atom connectivity while maintaining the same chemical formula)
Dominant form and typical base - pairing of nucleotides, this typical form of a nucleotide is called …
Keto form
Less frequent are the alternative ___ and ___ forms of nucleotides that changes the way base - pairing can happen
imino;enol
Depurination
The disruption of the bond between the sugar in the backbone and the A or G base
- occurs sponataneously all the time.
Deamination
The removal of an amino group from a base
Where does deamination commonly occur?
At the cytosine
Whether a mutation persists depends on 2 things …
- Whether DNA mismatch repair can occur before DNA replication
- If repair occurs before replication, which strand is used as the template for the repair
