8 - Mutations Flashcards
(15 cards)
What are two example of mutagenic agents?
High energy/ionising radiation
Carcinogens
How does high energy and ionising radiation affect DNA?
Damage and disrupt the structure of DNA.
What are the six gene mutations?
1) Addition
2) Deletion
3) Substitution
4) Inversion
5) Duplication
6) Translocation
What is an addition mutation?
One extra base being added to the sequence
What impact does an addition mutation have on the protein?
All codons after mutation are affected - frame shift. Altered codons could could for different amino acids and results in a different sequence in amino acid and into a non-functioning protein
What is a deletion mutation?
Deletion of a base in a sequence
What impact does a deletion mutation have on the protein?
Frame shift to the left. Results in a different polypeptide chain and non-functional protein
What is a substitution mutation?
One base changes to a different base
What impact does a substitution mutation have on the protein?
No frame shift. Only one codon changes. Genetic code is degenerate is may still code for the same amino acid and have no impact
What is an inversion mutation?
A section of DNA detaches and re-joins back to front
What impact does an inversion mutation have on the protein?
Results in different amino acids being coded for so different polypeptide
What is a translocation mutation?
A section of bases on one chromosome detaches and attaches to a a different chromosome
What is a gene mutation?
An alteration in a single base in the DNA base sequence of a gene which happens randomly and spontaneously
What effect does a gene mutation have?
Result in a different amino acid sequence in the encoded polypeptide. If amino acid sequence changes it modifies the tertiary structure and will form hydrogen and ionic bonds in different places. Resulting in a different 3D shape and therefore a non-functioning protein.
How do carcinogens affect DNA?
Chemicals that alter the structure of DNA and interfere with transcription (copying error in mRNA).
