Mutations Quiz
Which of the following is true of deamination (3)
It involves the removal of NH2 from a nitrogenous base It is responsible for the conversion of cytosine to uracil Occurs spontaneously in an aqueous environment
Which of the following DNA repair systems does not involve the activity of a DNA polymerase?
Photoreactivation in E.Coli
What do alkylating agents do?
They add methyl or ethyl groups to bases
Assume that you have discovered a new chemical mutagen that modifies guanine so that is mispairs with adenine when adenine is in the template DNA strand during DNA replication. However, this mispairing is limited to when the modified guanine is being added to the newly replicating DNA strand. When the modified guanine is in the template DNA strand it always pairs normally with cytosine being added to the growing newly synthesized strand. What type of mutation would you predict would be caused by the new chemical mutagen?
A-to-C base substitutions
Frameshift mutations (3)
Change many codons occur when DNA polymerase makes a mistake when copying long stretches of the same nucleotide usually produce nonfunctional proteins
How do germ-line mutations differ from somatic mutations?
Germ-line mutations result in mutant gametes, while somatic mutations do not.
Which of the following kinds of mutations is most likely to be null loss-of-function?
frameshift
In a double stranded DNA molecule a G is paired with a T. Which of the following statements are true (4)
This could be due to the deamination of a methylated cytosine. This could be due to DNA polymerase making a mistake during replication This could be corrected by DNA polymerase proofreading This could be corrected by Mismatch Repair if the DNA is hemimethylated
Loss of function mutations tend to be _______ because half the normal enzyme activity usually _______.
recessive; is sufficient to produce the wild type phenotype.
DNA polymerase's ability to proofread during replication should prevent
the incorporation of the wrong nucleotide because of wobble pairing