BIO2581 Section 003

what control point is associated with the silencing of target transcripts with both siRNA and miRNA?

• siRNA uses translational repression while miRNA uses post-transcriptional mRNA degradation
• miRNA uses translational repression while siRNA uses post-transcriptional mRNA degradation
• siRNA uses degradation at the level of splicing while miRNA uses degradation at the protein level
• miRNA and siRNA both use degradation at the level of translation
• mRNA isn’t degraded by either

Which of the following is an example of alternative splicing?

• An intron is removed from premrna before translation
• A gene produces multiple mrna variants by including or excluding specific exons
• RNA polumerase skips over an Econ during transcription
• The ribosome assembles different proteins from the same mrna transcript
• N/a

The lac operon controls the metabolism of lactose in bacteria. The lacI gene encodes the Lac repressor, which binds to the operator (O) and prevents transcription of the operon when there is no lactose. When lactose is present, allolactose binds to the Lac repressor, preventing it from binding to the operator and allowing transcription. lacZ contains the beta-galactosidase coding sequence. The superscript “-” indicates a loss of function mutation. The mutation lacIsr indicates a super repressor, meaning that the repressor cannot bind allolactose, so it will always be bound to the operator. The mutation Oᶜ indicates a constitutive operator, meaning that the operator is mutated and the lac repressor cannot bind, so transcription will always be turned on. A bacterial strain has the genotype I- O+ Z- / I- O+ Z-. Based on this genotype, what will be the expected phenotype of beta-galactosidase production when only glucose is present and when only lactose is present?

• A. Glucose: no beta-galactosidase expression, Lactose: beta-galactosidase expression
• B. Glucose: no beta-galactosidase expression, Lactose: no beta-galactosidase expression
• C. Glucose: beta-galactosidase expression, Lactose: beta-galactosidase expression
• D. Glucose: beta-galactosidase expression, Lactose: no beta-galactosidase expression
• E. None of the above

Expression or no expression of beta-galactosidase in glucose and lactose conditions? laci(SR) o(c) lacZ(-) / laci(-) o(+) lacZ(+) Glucose Lactose

• A: Expression No Expression
• B: Expression Expression
• C: No expression Expression
• D: No expression No Expression
• E: Small expression Expression

In Drosophila development, what would be the expected result of a gain of function mutation in Nanos, Pumilio, and 4EHP?

• Widespread Hunchback expression throughout.
• No Hunchback protein present.
• Hunchback expression only in the posterior.
• Hunchback expression only in the anterior.
• Increased Hunchback expression in both anterior and posterior regions.

If Nanos regulatory element is removed from the posterior, present in the anterior l; the Nanos gene is in its wildtype form in the posterior and the anterior, in which place(s) would you not find abdomen development?

• Posterior Only
• Anterior Only
• Posterior and Anterior
• Not in Posterior or the Anterior
• N/A

What is the main reason why GWAS can be used to associate a SNP to a given phenotype?

• The SNP results in a mutation in the coding region that results in the organism exhibiting that phenotype.
• The SNP can always be found in the same region of the genome as all other individuals of the same species.
• The SNP is inherited along with the causative allele due to it being in linkage disequilibrium
• The SNP is included in a gene that is related to the phenotype, causing the SNP to have a stronger association.
• N/A