Altering sequence of bases in DNA Flashcards
(14 cards)
What is a mutation?
A mutation is a change in the DNA base sequence.
Where can mutations occur?
In somatic cells, which may result in cancer. In gametes, where mutation will be passed on to the offspring if the cell with the mutation takes part in fetilisation.
What is a substitution mutation?
A substitution mutation is when 1 base is substituted for another.
What is a deletion mutation?
A deletion mutation is when 1 or more bases are lost.
What is an addition mutation?
An addition mutation is when 1 or more bases are added.
What is a duplication mutation?
A duplication mutation is when a sequence of bases or a whole gene is inserted twice or multiple times. This is important in expanding the genome as one of the genes can mutate and code for a new polypeptide while the original continues to work as normal.
What is an inversion mutation?
An inversion mutation is when a base sequence is removed, rotated by 180 degrees, and inserted back again. This mutation is very harmful as almost every codon is different.
What is a translocation mutation?
A translocation mutation is when a sequence of bases is taken out and inserted at a different position in the genome. This may be within the same chromosome or between different chromosomes.
Why are some mutations more harmful than substitution?
Addition, deletion, and duplication are all harmful as they cause a frame shift meaning every codon is read differently.
What is the importance of mutagenic agents?
Mutagenic agents increase the rate of mutations.
What is the importance of base analogs as mutagenic agents?
Base analogs can substitute for a base during DNA replication, which changes the base sequence in the new DNA.
What is the importance of some chemicals as mutagenic agents?
Some chemicals may delete or alter bases.
What is the importance of radiation as a mutagenic agent?
Radiation may alter the structure of DNA which causes problems during replication.
