Key Area 1.6 Flashcards
Name the types of mutations
- single gene mutation
- chromosome structure mutation
- polyploidy
Name the types of single gene mutations
- deletion
- insertion
- substitution
What is meant by a single gene mutation
Mutation which involved the change in one of the base pairs in the DNA sequences of a single gene
Describe a deletion (single gene) mutation
- one nucleotide is removed from a DNA sequence and not replaced
- this causes a frame shift so all codons after mutation are altered, causing different amino acids to be made
Deceive insertion (single gene) mutation
- This is when one nucleotide is added to DNA sequence
* this causes a frame shift so all codons after mutation are altered causing different amino acids to be made
Describe substitution (single gene) mutations
- this is when one nucleotide is removed and replaced by another
- this causes a missense mutation as only one codon is altered which may or may not affect protein produced
Name and describe the 4 possible effects of a single gene mutation
Missense:
occurs bc of SUBSTITUTION. Altered codon causes a diff amino acid to be made which still makes sense but not what was originally intended
Nonsense:
Occurs bc of SUBSTITUTION.
Codon which used to code for amino acid now codes for a stop codon. Causes protein statues is to be stopped early and causes polypeptide chain to be shorter than normal
Framshift:
Occurs bc of DELETION OR INSERTION.
affects triplet grouping on DNA sequence as every codon after the mutation is altered
It affects amino acid and overall the protein that is made
Name 4 chromosome structure mutations
Deletion
Duplication
Inversion
Translocation
Define the term mutation
The random change in the structure of amount of an organisms DNA
They are the only source of variation among a population
Describe a deletion (chromosome structure) mutation
Where a section of chromosome is deleted and gene are lost
Describe a duplication (chromosome structure) mutation
Where a set of genes are repeated
Describe an inversion mutation
Where a section of chromosome breaks off, rotates 180 degrees and reattaches
Describe a translocation (chromosome structure) mutation
What problems can this cause
Where a section of gene from one chromosome breaks off and joins another
Problems during gamete formation. Leads to non-viable gametes
Why are mutation important in the evolution
They are the only source of new variation and may give organisms an evolutionary advantage
Define the term polyploidy
Duplication of all the chromosomes, resulting in an extra set
