2. Gene Mutations Flashcards
If cell replication doesn’t go right, what may happen?
Gene mutations.
Mutations in the number of chromosomes.
Define gene mutation.
The change in the DNA base sequence of chromosomes.
Name the 2 types of errors in mutation.
Substitution.
Deletion.
What is the error substitution?
One base is substituted with another.
eg ATGCCT becomes ATTCCT - G swapped with T.
What is the error deletion?
One base deleted.
eg ATGCCT becomes ATCCT - G is removed.
Because the genetic code is degenerate, what does this mean for substitution?
Not all substitution mutations result in a change to the amino acid sequence of the protein - some substitutes with still code for the same amino acids.
What can tyrosine code for?
TAT.
TAC.
in DNA.
Despite substitution not always leading to a change in the amino acids, what does deletion do?
The deletion of a base will change the number of bases present, causing a shift in all the bases triplets after it.
3 DNA bases code for…
One amino acid.
Name 4 other possible errors?
Addition.
Translocation.
Insertation.
Duplication.
Name a way DNA can spontaneously mutate.
When DNA is misread during replication.
Define Mutagenic Agent.
Something that increases rate of mutations in DNA.
Give 3 examples of mutagenic agents.
Ultraviolent radiation.
Ionising radiation - X-ray, Gamma ray.
Some chemicals.
Chance.
Possibility that it will occur.
Probability.
Measure of how likely events are to happen.
0 - event is impossible.
1 - event is certain.
