38 Questions
What can lead to the formation of loops in the template strand during DNA replication?
Replication slippage
Which genetic disorder can result from the skipping over of loops by DNA polymerase during replication?
Fragile-X syndrome
What process involves the spontaneous change from one tautomer to another, leading to non-complementary base-pairing?
Tautomeric shifts
What is the term for the random loss of a nucleotide's purine base?
Depurination
Which mutagen can add bulky carbon chains like methyls or ethyls to DNA bases?
Alkylating agents
What type of radiation sensitivity can base analogs contribute to?
UV radiation sensitivity
If cytosine loses an amino group and an oxygen is added in its place, what base does it change to?
Uracil
Which process involves the filling of an apurinic site with an adenine nucleotide?
Depurination
What is the function of enhancers in gene regulation?
Enhancers can enhance any gene nearby
Which of the following actions do silencers perform in gene regulation?
Silencers block enhancers to inhibit gene expression
What effect does methylation of DNA have on transcription?
Methylation inhibits transcription
What is RNA-induced gene silencing?
A type of RNA interference regulating translation
Which enzyme is responsible for cleaving double-stranded RNA during a viral infection to produce siRNA?
Dicer
What is the function of microRNA in gene expression regulation?
MicroRNA inhibits gene expression
Which complex is responsible for RNA-induced silencing in gene regulation?
RISC: RNA-induced silencing complex
What is the role of a repressor protein in negative control?
Inhibits transcription
Which of the following describes the function of the allosteric domain of a repressor protein?
Binds a molecule to change DNA binding domain shape
What is the main function of an activator protein in positive control?
Initiates transcription
How do most activator proteins become active for transcription initiation?
Bonding with an allosteric compound
What factor is expressed during the heat shock response due to unstable conditions?
Alternative sigma factor (sigma 32)
What role do chaperone proteins play in the heat shock response?
Inhibit sigma 32 at hot temperatures
What are riboswitches and how do they control gene expression?
Noncoding mRNA segments controlling downstream gene expression by metabolite binding
Which DNA repair mechanism involves the swapping of genetic material between homologous DNA molecules?
Homologous recombination
Which stage of meiosis does homologous recombination occur in eukaryotes?
Prophase I
Which type of mutation results in the translation being stopped early due to a stop codon?
Nonsense
Which type of mutation results in a triplet code that still codes for the same amino acid?
Silent
Which mechanism of DNA repair is likely to involve kinase and BRCA1?
Nonhomologous end joining
Which hypothesis suggests that mutations arise from adaptations to the environment?
Adaptation hypothesis
Which type of mutation involves the replacement of one pyrimidine by another?
Transition
Which type of mutation involves the replacement of a pyrimidine by a purine or vice versa?
Transversion
What type of mutation can be caused by the addition of bulky adducts?
Frameshift mutation
How do hydroxylating agents cause mutations?
By adding hydroxyl groups to bases
What type of damage can be caused by transposable DNA elements?
All of the above
What type of radiation can produce reactive oxygen molecules that damage DNA?
Ionizing radiation
What is the role of activator proteins in transcriptional regulation?
They bind regulatory sequences to stimulate transcription
What is the role of repressor proteins in transcriptional regulation?
They bind other sequences to stop or slow transcription
What is a characteristic of enhancers and silencers in eukaryotes?
They are non-coding DNA regions
What is the purpose of the Ames test?
To determine if a chemical can cause DNA mutations in bacteria
Test your knowledge on the two main DNA repair mechanisms: homologous recombination and nonhomologous end joining. Learn about how genetic material is swapped between homologous DNA molecules and the process of repairing double strand breaks.
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