8.1 Flashcards
What is a mutation
An alteration to the base sequence. Often arise spontaneously during DNA replication
What are addition and deletion mutation s
Where one or more nucleotides (bases) are inserted or deleted from the DNA sequence
What is a substitution mutation
where one nucleotide (base) in the DNA sequence is replaced by another
What is a duplication mutation
Where one or more nucleotides (bases) duplicate and repeat
What is a duplication mutation
Where one or more nucleotides (bases) duplicate and repeat
What is an inversion mutation
Where a group of nucleotides (bases) become separated from the DNA sequence then rejoin in the reverse order
What is a translocation mutation
Where a group of nucleotides (bases) become separated from the DNA sequence and are then inserted into the DNA of a different chromosome
Which mutations are most likely to have a significant impact and why?
Insertion, deletion, duplication, translocation. Because they produce a frameshift, meaning the entire amino acid sequence produced will be different
Which mutations are less likely to have a significant impact and why?
Substitution, inversion. Because they only alter one or very few triplets, the amino acid sequence might not be affected due to the degenerate nature of the genetic code
Is a mutation resulting in a change to the amino acid sequence always harmful?
No: may be neutral if the resulting change in the protein has no effect on the organism.
Also may be beneficial which is the basis for evolution and natural selection
What is a mutagenic agent? Give examples
Factors that increase the rate of gene mutation.
Chemical mutagens such as alcohol and benzene. Ionising radiation such as UV and X-ray
