6.1.1 Cellular control Flashcards
What is a mutation?
Change in sequence of of bases in DNA
What is a point mutation?
Only one nucleotide is affected
What three things causes a mutation?
Insertion
Deletion
Substitution
(of one or more nucleotides or base pairs)
What is a mis-sense mutation?
Different amino aicds in the sequence: two types are conservative and non-conservative
What is a conservative mis-sense mutation?
Changed amino acid is chemically similar to the the previous amino acid so secondary and tertiary structure is unaffected
What is a non-conservative mis-sense mutation?
Changed amino acid is chemically different to the previous amino acid and so secondary and tertiary structure is affected
What is a non-sense mutation?
Protein is truncated (due to STOP codon) so it is no longer functional
What is a silent mutation?
Shape of the protein/amino acid sequence is unaffected
Why does a silent mutation occur?
Due to the degenerate nature of the genetic code (multiple codons code form one amino acid)
What is an example of a silent mutation?
Base substitution
What is a frameshift mutation?
Every adjacent base shifts from the point of mutation
Why does a frameshift mutation occur?
Due to the non-overlapping nature of the genetic code (each codon is read separately)
What is an example of a frameshift mutation?
Base deletion
Base insertion
What are the types of chromosome mutations?
- Deletion: section breaks off and is lost
- Duplication: section gets duplicated
- Translocation: section breaks off and joins another non-homologous chromosome
- Inversion: section breaks off, is reversed and then joins back onto the chromosome
What is an example of a beneficial mutation
Lactose digestion
