mutations Flashcards
what is a mutation?
A mutation is a change to the base sequence in the DNA. All alleles of genes are a result of a mutation.
what 3 things can mutations be caused by?
addition, deletion and substitution of bases
what is an addition mutation?
where one or more bases are added to the sequence
what is a deletion mutation?
where one or more bases are removed from the sequence
what is a substitution mutation?
when one or more bases are changed in the DNA sequence
what can mutations be caused by?
an error during the DNA replication process or by DNA/RNA polymerase. These are spontaneous. Also, by mutagenic agents, which are physical or chemical agents that increase the probability of mutations occurring such as high energy radiation (UV) or chemicals that change the structure/transcription process. Finally, mutations can be caused by viruses
explain chromosome mutations/non-disjunction
this occurs when chromosomes don’t split correctly during meiosis so the gametes don’t have the correct number of chromosomes. This is non-disjunction. This can cause things like down syndrome
why are mutations harmful?
they change the primary structure of a protein and so disrupt the normal functioning of a protein
what is a mutagenic agent?
a physical or chemical agent which increases the probability of a mutation
when would a mutation have a positive affect on an individual?
when it increases survival rate and makes them better adapted to their environment so there is more reproductive success
What is an allele?
Different versions of the same gene.
