Alteration Of The Sequence Of Bases In DNA Can Alter The Structure Of Proteins Flashcards
when may gene mutations arise?
during DNA replication, S-phase
what are the types of gene mutations(6)?
- addition
- deletion
- substitution
- inversion
- duplication
- translocation
= of the bases
what is addition?
one base is inserted into a sequence
what is deletion?
one base is lost from the sequence
what is substitution?
one base is replaced for another (unless the substitution causes a stop)
what is inversion?
a double stranded section of DNA containing all or part of a gene is reversed
what is duplication?
a double stranded section of DNA containing all or part of a gene is copied twice or multiple times
what is translocation?
a double stranded section of DNA containing all or part of a gene is repositioned
how do gene mutations occur?
they occur spontaneously
how can the mutation rate be increased?
increased by mutagenic agents
what can mutations result in?
- different amino acid sequences in the encoded polypeptide
what do gene mutations lead to?
- change in only one triplet code = degenerate nature of genetic code, not all mutations result in the change of the encoded amnio acid
- change the nature of all base triplets downstream from mutation = frame shift
