2.5 Changing Code through Mutations. Flashcards
What is Mutation?
A mutations is where there are changes to DNA sequence, at the gene or chromosomal level.
What is DNA replication, what happens during it and when does it occur?
DNA replication is where DNA is duplicated. It first starts when the DNA is ‘unzipped’ and then a new complementary strand is created for it. It occurs during interphase of Meiosis and Mitosis.
What are the types of mutation?
Spontaneous mutation and induced mutation.
What is spontaneous mutation?
It is a mutation of DNA that the cause cannot be explained or identified.
What is induced mutation?
a mutation of DNA in which the cause can be identified.
What is a mutagen and what are some examples?
A mutagen is something that induces mutations. Some examples are radiation, chemical substances (asbestos, tobacco) and infectious agents (HPV).
What are substitution mutations?
It is where one base is replaced by another.
What are missense mutations (a type of substitution mutation)?
where one amino acid is swapped for another (as seen in sickle-cell anaemia)
What are silent mutations (a type of substitution mutation)?
Silent mutations: no change occurs in the amino acid.
What are Nonsense mutations (a type of substitution mutation)?
where an amino acid is changed to a STOP codon (causing a shortened protein).
What are frameshift mutations?
It is where a nucleotide is added altering the entire amino acid code. e.g UCA AUC becomes UCA AAU C
What is a point mutation?
It is a mutation at one particular point in the DNA sequence, such as a substitution or single base deletion or insertion.
Are mutations harmful at all?
They can either be helpful, harmful or not make difference.
Why are some mutations not inherited?
Mutations that occur in somatic cells are not passed on.
