Which of the following environmental conditions would be MOST likely to result in transcription of the lac operon in an E. colicell? A. low levels of lactose and high levels of glucose B. high levels of lactose and high levels of cyclic AMP C. low levels of lactose and low levels of cyclic AMP D. high levels of lactose and high levels of glucose

Explain and give an example (lac operon) of how inducer operons function in prokaryotes.

The E. coli lacZYA región will be transcribed at a rate greater than the low basal rate if: A. glucose and lactose are both present in the growth medium, but there's a defect in the cells ability to synthesize cAMP B. there is a defect in binding of the inducer to the product of the lacl gene C. glucose and lactose are both readily available in the growth medium D. the operator has mutated so it can no longer bind repressor  E. none of the above

Which of the following statements about trp operon regulation is TRUE? A. Low trp levels result in trp repressor binding. O B. High trp levels result in transcriptional antitermination. C. Low trp levels cause the ribosome to fall off at the trp codons in the upstream ORF. O D. High trp levels cause the ribosome to fall off at the trp codons in the upstream ORF. O E. Low trp levels result in transcriptional antitermination. QUESTION 34 Consider the following partial diploid for the lac operon system. lacl+ O+ lac Z+Y-A- lacls O+ 1. 2. lac Z-Y+ A+ In this configuration, which of the following statements is TRUE? A. With no lac present, ZYA will all be expressed. B. with lac present none of the genes (ZYA) will be expressed. O C. With no lac present, only YA will be expressed. D. None of these answers is correct. E. With no lac present, only Z will be expressed.

A mutation occurs in the lac operon operator site such that LacI can no longer bind to the operator site. The effect that this mutation has on the cell is that a. the activity of the lac operon will not be affected. b. the cell can no longer convert lactose to glucose. c. the expression of the lac genes cannot be turned off. d. the expression of the lac genes cannot be turned on.

Which of the following statements is true regarding transcriptional attenuation of the trp operon? a. The leader peptide encodes a protein that binds to the operator site b. Translation of the leader peptide stalls when tryptophan levels are high c. Stalling of the ribosome in region 1 of the leader peptide inhibits formation of the transcriptional terminator sequence d. This kind of mechanism can only occur in prokaryotes e. Both c. and d. are true

Explain how the lac operon is regulated under the following conditions. Include the following terms in your answers: Repressor, Operator, RNA polymerase, CAP site, CAP protein, Promoter A. Lactose and glucose are both present. B. Lactose and glucose are both absent. C. Lactose is present and glucose is absent.

You are growing E. coli in a laboratory in order to study their operons. The growth media you are using contains lactose, no glucose and no tryptophan.  Using your knowledge of operons and their regulation   a.Which operons would be functional under these conditions? b.What repressors would be made? (NOTE: name the repressors using their gene names) c.Which repressor(s) would be made in the inactive form? d.Which repressor(s) would be made in the active form? e.Which repressor(s) under these conditions can bind the operator sequence? f.Which repressor(s)under these conditions cannot bind the operator sequence?

Which of the following statements about the lactose operon in E. coli is FALSE? Choose an answer below: It contains the genes that encode the proteins for lactose metabolism. Its transcription is induced when allolactose binds to the lac repressor. It contains a promoter and an operator. It is strongly transcribed when lactose is present in the medium and glucose is absent. none of the above

In the tryptophan operon, if the leader peptide is translated normally   A region 2 will pair with region 3   B a rho independent terminator will form.   C both a and b   D none of the above