9.1 Gene mutation Flashcards
(16 cards)
What is a mutation?
A sudden change in the amount or the arrangement of the genetic material in the cell.
What is a gene mutation?
A sudden change in the amount or the arrangement of the nucleotide bases.
What does gene mutation involve?
A change in the base sequence of chromosomes
When does gene mutation arise spontaneously most likely?
During DNA replication
What are the types of gene mutation?
- substitution of bases
- deletion of bases
(3. insertion of bases)
Do all substitutions of bases cause a change in the sequence of encoded amino acids? Why?
No, because genetic codes are degenerate (most amino acids are coded for by more than one triplet).
What is called when another base substitutes a base but still gets the same amino acid?
Silent mutation
Do deletions of bases cause a change in the sequence of encoded amino acids?
Yes
What is a chromosome mutation?
A sudden change in the structure or the number of whole chromosomes.
In which two forms can chromosome mutation arise spontaneously?
- changes in whole sets of chromosomes
- changes in the number of individual chromosomes
What does change in whole sets of chromosomes mean?
When organisms have three or more sets of chromosomes rather than two.
What is the change in whole sets of chromosomes known as?
Polyploidy
What does change in the number of individual chromosomes mean?
When individual homologous pairs of chromosomes fail to separate during meiosis.
What is the change in the number of individual chromosomes known as?
Non-disjunction
What can increase the rate of gene mutation?
Mutagenic agents
What are the examples of mutagenic agents?
- gamma rays
- UV light
- viruses
- nitrous acid
