7.1 Mutations: Primary Tools of Genetic Analysis Flashcards
What are mutations
They are changes in the DNA base sequences
What does a forward mutation do?
It changes the wild-type allele to a different allele.
What does a reverse mutation (reversion) do?
It changes a mutant allele back to the wild-type allele
What are the 3 classifications of mutations by effect on the DNA molecule? (point mutations)
substitution, insertion, Deletion
What is a substitution mutation
It is when a specific base is replaced by another different base
What are the two types of substitution mutations
Transition and transversion
Explain what a transversion mutation is
It is when a purine is replaced by a pyrimidine or vice versa.
Explain what a transition mutation is
It is when a purine is replaced by another purine or when a pyrimidine is replaced by a different pyrimidine
What is a deletion mutation
It is when a block of 1 or more base pairs are lost from DNA
What is an insertion mutation
It is when a block of 1 or more base pairs are added to DNA
What are two facts about spontaneous mutations
They occurvat a very low rate and arise from random events
true or false: different genes= different mutation rates
true
Mutations are _________ per gene per gamete
<10^-9 to> 10^-3
Why is it that different genes have different mutation rates? (2)
- Differences in gene size
- Some genes are more susceptible to mutations
true or false: The average mutation rate in gamete producing eukaryotes is less than that of prokaryotes
false, it is higer
why is the average mutation rate in gamete-producing eukaryotes is higher than that of prokaryotes?
Many cell divisions take place between zygote formation and meiosis in germ cells, which increases the chance of errors= higher chance of mutations
Why can diploid organisms tolerate more mutations than haploid organisms
This is because diploid organisms have two copies of the genome while haploid organisms have one copy.
Why is it that human sperm have higher mutation rates than human eggs
This is because male germ cells undergo mitosis continuously. Hence there are more mutations in the sperm of older men
true or false: most mutations don’t influence phenotype
true
true or false: revertants are more common than forward mutations
false, they are more rare. Many mutation disrupt gene function, only a few restore function
define colony
a visible mass of microorganisms that are all genetically identical and come from a single mother cell
