Question | Answer |
List 3 things that can cause mutation | a mistake in the DNA-dependent DNA polymerase, chemicals found in the environment, ultraviolet rays from the sun and tanning lights |
What process causes spontaneous genetic change? | mutation causes spontaneous genetic changes |
What is a heritable change in the base sequence of DNA called? | heritable change in the base sequence of DNA called is a mutation |
Nonsense mutation | gives rise to a stop codon in the middle of a gene so that translation stops before it is complete |
Frame-shift deletion | indicates that nucleotides, perhaps one or two (not 3) have been deleted from a gene--downstream codons no longer in register |
Give an example of phenotypic and genotypic changes in lac operon | mutation in undefined area of lac operon--3 structural genes/control operator regions--result in cell becoming phenotypically lactose-= mutation known to render lacZ gene nonfunctional--lacZ genotype |
which of the changes--phenotypic/genotypic would produce a lactose auxotroph? | both--mutants would be unable to utileze lactose--both would be lactose auxotrophs |
How might regulatory mutations in the lac operator or promoter affect cell function? | mutant lac operator--no binding to repressor--lactose operon would be expressed constitutively==mutant lac promoter--unable to bind RNA polymerase--no transcription/expression possible |
What does the Ames test show? | whether chemicals increase the frequency of mutations--if frequency increases--chemical under question called mutagen/carcinogen |