9.1 - Gene Mutation Flashcards
(14 cards)
Any change to the quantity or the base sequence of the DNA of an organism is known as what?
A mutation
Any change to one or more nucleotide bases, or a change in the sequence of the bases, in DNA is known as what?
Gene mutation
The type of gene mutation in which a nucleotide in a DNA molecule is replaced by another nucleotide that has a different base is known as a what?
Substitution of bases
The severity of substitution of bases is determined by what?
The precise role of the original amino acid
In what way could the substitution of bases could not change anything?
If the base that has been substituted still codes for the same amino acid because it is degenerate
What type of mutation is it when a nucleotide is lost from the normal DNA sequence?
Deletion of bases
Is the deletion of bases bad?
The consequences can be considerable
Why is the deleation of bases bad?
One deleted nucleotide causes all triplets in a sequence to be read differently because each has been shifted to the left by one base.
Changes in the structure or number of whole chromosomes are called?
Chromosome mutations
Chromosome mutations can arise spontaneously and take two forms which are?
- Changes in whole sets of chromosomes
- Changes in the number of individual chromosomes
When do changes in whole sets of chromosomes occure?
When organisms have three of more sets of chromosomes rather than the usual two
What is the condition called and where does it occur mainly when there are changes in whole sets of chromosomes?
Polyploidy - occurs mostly in plants
How do changes in the number of individual chromosomes occur?
When individual homologous pairs of chromosomes fail to separate during meiosis
What is it called when the homologous pairs fail to separate during meiosis?
Non-disjunction
