Micro: Ch 17 Mutations

Front 1

List three things that can cause mutation

Back 1

Three things that can cause mutation are as follows: a mistake in the DNA-dependent DNA polymerase; chemicals found in the environment; and ultraviolet rays from the sun and tanning lights

Front 2

What process causes spontaneous genetic ∆?

Back 2

Mutation causes spontaneous genetic changes.

Front 3

What is the heritable ∆ in the base sequence of DNA called?

Back 3

mutation

Front 4

Nonsense mutation (d)

Back 4

gives rise to a stop codon in the middle of a gene so that translation stops before it is complete

Front 5

Frame-shift deletion

Back 5

Indicates that nucleotides, perhaps one or tow (not three), have been deleted from gene so that downstream codons are no longer in register.

Front 6

Give an example of phenotypic and genotypic changes in the lac operon.

Back 6

A mutation in an undefined area of the lac operon, and of the three structural genes or the control promoter or operator regions could result in the cell becoming phenotypically lactose neg. If we knew that the mutation specifically rendered the lacZ gene nonfunctional, we would call it lacZ genotype.

Front 7

Which of the phenotypic or genotypic changes would produce a lactose auxotroph?

Back 7

Both of the above mutants would be unable to utilize lactose; therefore, both would be lactose auxotrophs.

Front 8

How might regulatory mutations in the lac operator or promoter affect cell function?

Back 8

A mutant lac operator would not bind the repressor, so the lactose operon would be expressed constitutively. A mutant lac promoter would be unable to bind RNA polymerase so no transcription or expression would be possible.

Front 9

What does the Ames test show?

Back 9

The Ames test shows whether test chemicals increase the frequency of mutations. If the frequency increases, the chemical under question is called a mutagen or even a carcinogen.