Genetics Chapter 16

In Jacob, Monod, and Pardee's experiment, how many functional copies of lacl were there in the merozygote?

1

What stem-loop conformations favor attenuation in the trp operon?

3-4

What would be the result if the U-rich sequence after the fourth stem loop in the trp operon was replaced by a UG-rich sequence?

Attenuation would not occur if tryptophan was high.

In the Jacob Monod merozygote experiment, what was indicated by the presence of a yellow color when b-ONPG was added?

Beta-galactosidase was present.

Antisense RNA does which of the following?

Binds to a complementary RNA and prevents its translation

In Jacob, Monod, and Pardee's experiment, what would have been the conclusion if all four tubes produced a yellow color when β-ONPG was added?

Expression of the lac operon is constitutive whether lacI is functional or not

Enzymes involved in metabolism are most likely regulated via _____.

Feedback inhibition

A mutation in the lacI gene prevents the gene product from binding allolactose. What will the expression level of the operon be in the absence of lactose?

No transcription

Which of the following is not an example of translational regulation in prokaryotes?

Phosphorylation of an enzyme Are examples: - Binding of antisense RNA to mRNA - Altering the structure of the mRNA - Sterically blocking the ribosome

Which of the following is found in an operon?

Promoter, terminator, two or more genes, operator

CAP affects which operon(s)?

The lac operon

If the Trp codons in the trpL gene were mutated to encode another amino acid, what would the result be?

The trp operon would never be transcribed.

Riboswitches have been shown to affect regulation of ______.

Transcription and translation

If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario.

Transcription would be difficult to activate in the absence of glucose

Regulation of gene expression may occur at which of the following levels?

Transcription, translation, post translation

8. In a particular E. coli strain, a mutation in the thiMD operon results in improper formation of the stem loop secondary structure making it impossible to bind TPP. There are two enzymes encoded by the thiMD operon. How many of the enzymes encoded in the thiMD operon are translated?

Two

Translational regulatory proteins recognize specific areas of what molecule?

mRNA

A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene?

repressor + inducer

What is the gene responsible for attenuation in the trp operon?

trpL