Mutations Flashcards
What is a gene mutation
Alteration of a base sequence for one gene.
When is a gene mutation likely to occur?
Spontaneously during DNA replication, during interphase.
What is the consequence of gene mutations in terms of proteins?
- When protein is modified into tertiary structure it will form H bonds and Ionic bonds in different places
- Folds differently
- Different 3D shape/tertiary structure
- Protein will have a different function/non functioning
- Active site no longer complementary to substrate.
What are the two mutagenic agents?
High energy and Ionising Radiation:
(radiation and ultraviolet light)
Carcinogens:
chemicals that alter the structure of DNA and interfere with transcription
(tobacco smoke, mustard gas, peroxides)
What is an Inversion mutation?
A section of the DNA detaches from the DNA sequence and rejoins inverted
- section of code is back to front
Impact of inversion mutation?
Results in different amino acids being coded for in this region
- Affects the resulting polypeptide chain and therefore final protein
What is translocation?
A section of bases on one chromosome detaches and attaches to a different chromosome
Impact of translocation?
Significant impact on gene expression as section of chromosomes is likely to be multiple genes
- lots of proteins will be incorrect for the particular cell
- can result in change of phenotype
What is duplication?
A whole gene or section of a gene is duplicated so that two copies of the gene/section appear on the same chromosome
Impact of duplication?
Overtime, the second copy can undergo mutations which enable it to develop new functions
- source of evolutionary change
