Mutations and Gene Expression Flashcards
Substitution Mutation
One or more bases are swapped for another
eg ATGCCT becomes ATTCCT
Deletion Mutation
One or more bases are removed
eg ATGCCT becomes ATCCT
Addition Mutation
One or more bases are added
eg ATGCCT becomes ATGACCT
Duplication Mutation
One or more bases are repeated
eg ATGCCT becomes ATGCCCCT
Inversion Mutation
A sequence of bases is reversed
eg ATGCCT becomes ACCGTT
Translocation Mutation
A sequence of bases is moved from one location in the genome to another.
This could be the movement within the same chromosome or movement to a different chromosome
What does the order of DNA bases in a gene determine?
The sequence of amino acids in a particular polypeptide
Effect of a mutation occurring in a gene
The sequence of amino acids in the polypeptide that the gene codes for could be changed
Hereditary Mutations
If a gamete containing a mutation for a genetic disorder or a type of cancer is fertilised, the mutation will be present in the new fetus formed
Genetic Disorders
Some mutations can cause inherited disorders caused by abnormal genes or chromosomes.
Some mutations can increase the likelihood of developing certain cancers
Degenerate Nature of Genetic Code and Mutations
What does this result in?
Means that some amino acids are coded for by more than one DNA triplet.
Not all types of mutation will always results in a change to the amino acid sequence of the polypeptide
Which types of mutations usually always cause a change in the amino acid sequence of a polypeptide?
Additions
Duplications
Deletions
Why do some mutations almost always cause a change in the amino acid sequence of a polypeptide?
Because these mutations all change the number of bases in the DNA code (additions, duplications, deletions)
Frameshift
A shift in the base triplets that follow, meaning that the triplet code is read in a different way
Downstream of a Mutation
The base triplets that follow on from the mutation
