Molecular Genetics Ch. 19 - Learnsmart
Steps of homologous repair
DSB is processed at break site strand exchange DNA synthesis resolution and ligation
Eukaryotic homologs for which of the following have been found so far?
MutS and MutL
MutL
acts as a linker that helps loop the DNA
In a neutral mutation, a negatively charged amino acid is substituted for _____________.
another negatively charged amino acid
A mutant Drosophilia fly can land on the side of a fly bottle when the bottle in incubated at 20 - 23 degrees but not at 24 - 27 degrees. This is an example of a(n) ____________ mutation.
conditional
MutS
detects the mismatch
Exonuclease
digests the nonmethylated strand
The addition or deletion of a number of bases that is not a multiple of 3 causes a(n) ___________ mutation.
frameshift
What can cause double-strand breaks (DSBs)?
gamma rays reactive oxygen species x-rays
Defects in the human mismatch repair genes, hMSH2 and hMLH1, play a role in the development of ________.
hereditary nonpolyposis colorectal cancer
Double-strand breaks are typically repaired by which of the following?
homologous recombination repair nonhomologous end joining
The restoration of protein function by a second mutation in a different gene is known as a(n) _______________.
intergenic suppressor
The restoration of function by a second mutation at a different site in the same gene is known as ____________.
intragenic suppressor
Error-prone replication is a characteristic of __________.
lesion-replicating polymerases
MutH
makes a cut in a nonmethylated strand
An individual that has one copy of the sickle cell allele and one copy of the wild-type allele has an increased level of resistance to the disease __________.
malaria
An allele that has a DNA sequence different from that of the wild-type is called a(n) __________ allele.
mutant
A heritable change in genetic material is called ______.
mutation
A mutation that results in a premature termination of the synthesis of a polypeptide is called a(n) ______________ mutation.
nonsense
Which mutation changes a mutant allele back to a wild-type allele?
reversion
MutU
separates strands at the cleavage site
A main advantage of nonhomologous end joining is that it does not require an _________ _________, and this it can take place throughout the cell cycle.
sister ; chromatid
A second mutation that occurs in a different site than the first mutation, and which converts the mutant back to the wild-type phenotype, is best referred to as a(n) ___________ mutation.
suppressor
The strand that is repaired in the mismatched repair system is _____________.
the nonmethylated strand
The wild type genotype or phenotype is the one that is _________ found in nature.
typically
Mutations that occur in a promoter sequence can be divided into two types: _________ promoter mutations increase the transcription rate, while _____________ promoter mutations decrease it.
up ; down
A breakpoint refers to the region ____________.
where two chromosomes pieces break and rejoin with other chromosome pieces within a gene