Chapter 19
which of the following base changes are transversion mutations? 1) A to T 2) G to C 3) A to G 4) A to C 5) C to T 6) G to A
1) A to T 2) G to C 4) A to C
assume a tautomeric shift occurred, which was followed by two rounds of DNA replication. If the mutation is not repaired, the result would be an:
AT to GC mutation in one of the four daughter molecules
which of the following are tautomers? Amino Imino Keto Enol Acetal
Amino Imino Keto Enol
A silence mutation is a mutation that results in:
No change to the amino acid sequence of the polypeptide
double strand break
The breakage of chromosomes
oxidative stress
The imbalance between an organism's production of ROS and the ability to break them down
mutations in the 5'-UTR or 3'-UTR of an mRNA molecule are most likely to affect what?
The mRNA's ability to be translated and The stability of the mRNA
trinucleotide repeat expansion
The phenomenon in which a repeated sequence of three bases increases in number generation after generation
Depurination
The removal of a purine from DNA
nonsense mutation
a base substitution in DNA that ultimately leads to a change from a normal codon to a stop codon
Missense mutation
a base substitution in DNA that ultimately leads to a change in the encoded amino acid
transversion mutation
a base substitution in which a purine and a pyrimidine are interchanged
neutral mutation
a missense mutation that has no detectable effect on protein function
tautomeric shift
a temporary change in base structure due to movement of hydrogen atoms
transition substitution
a type of base substitution that involves a change of a pyrimidine to another pyrimidine or a purine to another purine
genetic anticipation
an increase in severity of the symptoms as a disease is passed through future generations
during the normal course of DNA replication, the addition of a nucleotide that does not obey the AGC rule of base pairing creates a what?
base pair mismatch
a change of one base for another
base point mutation or base substitution mutation
base analogs induce mutations by
being incorporated instead of normal bases during DNA replication
What are two enzymes that cells use to prevent the buildup of reactive oxygen species?
catalase superoxide dismutase
oxidative DNA damage
changes in DNA structure that are caused by reactive oxygen species (ROS)
which base is most readily deaminated?
cytosine
The removal of an amino group from a base is called what?
deamination
What is the correct order of steps during a typical DNA repair system?
detection --> removal --> replication
the mutation rate
expressed as the number of new mutations in a given gene per cell generation
What can cause double-strand breaks?
gamma rays x-rays reactive oxygen species
double-strand breaks are typically repaired by what?
homologous recombination repair non homologous end joining
for a tautomeric shift to cause a mutation, when must it occur?
immediately prior to DNA replication
Alkylating agents covalently attach ____ or ____ groups to DNA bases, and thus disrupt their normal base pairing properties
methyl ethyl
reactive oxygen species
products of oxygen metabolism in all aerobic organisms, such as hydrogen peroxide, superoxide, and hydroxyl radical
The covalent bond between deoxyribose and appearing base is rather unstable and can undergo a spontaneous reaction with water. The breaking of the bond releases the base, and leaves a _____ site in the DNA.
purinic
mutations and eukaryotic genes that change the _____ recognition sequences may affect the order and/or number of exons contained in the mature mRNA
splice
frameshift mutation
the addition or deletion of a number of bases that is not a multiple of 3
which test is used to evaluate the mutagenicity of an agent?
the ames test
translesion synthesis
the synthesis of DNA over a template strand that harbors some type of DNA damage
ultraviolet light (non-ionizing radiation) causes the formation of cross-linked what in DNA?
thymine or pyrimidine dimers
The base cytosine is deaminated to produce the base _______
uracil