Bio 112

Which of the following is FALSE about transcription? Choose all that apply

A. The RNA transcript made is identical to a specific region of DNA (with the exception of U replacing T)

B. A RNA polymer is made from ribonucleic acid monomers

C.Polymerization becomes more stable because RNA monomers lose motional freedom D. Transcription always occurs in the nucleus. E. Sequence errors in a RNA transcript are passed on from one generation of cells to the next.

C: Polymerization does not provide stability in RNA. in fact when molecule are locked and not moving means there low entropy and a decrease in entropy is unfavourable not stabilizing

D: transcription does not always occur in the nucleus for prokaryotes it occurs in the cytoplasm

E: Errors in RNA transcripts are not inherited because RNA is not replicated or passed to daughter cells.

What is the TFIIB

A transciption binding factor that helps RNA polymerase bind correctly

Which of the following statements about operons in prokaryotes is correct (choose all that apply)

A. Each section of the mRNA encoding one polypeptide must have an upstream ribosome binding site.

B. There is one promoter controlling gene expression of all of the genes.

C. Each ORF has its own promoter.

D. The ORFs are regulated as a cluster.

E. RNA Polymerase transcribes the polycistronic mRNA

A: In a polycistronic mRNA each, open reading frame encodes for a different protein

B: There is one promoter controlling gene expression of all the genes

C: INCORRECT —> each ORF has it’s own RNA binding site but shares a single promoter

D: The ORF’s are regulated as a cluster, all genes in an operon are turned on together and turned off together, this allows coordinated expression of related proteins

E: RNA polymerase transcribes the polycistronic RNA

Why are operons in prokaryotes different than splice variants in eukaryotes?

A. In operons, each protein is encoded on a separate mRNA, but splice variants share a primary transcript.

B. In operons, transcription regulated, but there is no transcriptional regulation in primary mRNA transcripts.

C. In both operons and splice variants, the mRNA must be processed before translation.

D. In operons, each protein is encoded in a unique sequence on part of the one mRNA, but splice variants proteins are made up of many of the same exons.

A: INCORRECT because the characteristic is that there is one RNA that produces many proteins, spliced variants do share a transcript but they have different processed forms

B: INCORRECT in all cases there is regulation in gene expression

C: INCORRECTin operons there is no mRNA being processed in eukaryotes there is processing (splicing, 5’ cap)

D:CORRECT

If there is a frameshift mutation in the N terminus of the lacI gene, how would expression of the lac operon be affected?

Choose all that apply.

A. There would be no expression of the lac operon in the presence of lactose.

B. There would be no expression of the lac operon in the absence of lactose.

C. There would be expression of the lac operon in the presence of lactose. D.There would be expression of the lac operon in the absence of lactose.

C

D

when there is an absence of lactose in the cell, the repressors job is to stop expression of the operon. When no lactose the proteins are not required, waste of energetic expense. cell could be using that energy on other things (growth, metabolism of other things)