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 or more bases are added to the sequence
what is deletion?
one or more bases are removed from the sequence
what is substitution?
one or more bases are swapped for another (unless the substitution causes a stop)
what is inversion?
the sequence of bases is reversed
what is duplication?
one or more bases are repeated
what is translocation?
sequence of bases is moved from one location in the genome to another
- this movement can be within the same chromosome or to a different chromosome
how do gene mutations occur?
they occur spontaneously during DNA replication
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
what is a frame shift mutation?
- likely due to addition, duplication or deletion
- changes the amino acid sequence for polypeptide (changes number of bases in DNA code)
- triplet code is read in a different way
