Question

1. The terminating "hairpin" loop occurs in the tryptophan operon when ________.

A. sufficient glucose is present.

B. sufficient tryptophan is present.

C. insufficient tryptophan is present.

D.	insufficient glucose is present.

E. None of the above

2. When tryptophan is present in the medium and available to the bacterium, ________.

A. the repressor is inactive and the tryptophan operon is "off"

B. the repressor is inactive and the tryptophan operon is "on"

C. the repressor is bound to the operator, thus blocking transcription

D. the five structural genes associated with tryptophan synthesis are being transcribed at "induced" levels

E.positive control is occurring

3. What occurs in a bacterium with respect to genetic regulation of the tryptophan operon?

A. when there are high levels of tryptophan in the medium, transcription of CAP (CRP) occurs at high levels

B. when there are high levels of tryptophan in the medium, ribosomes "stall" and reduce the levels of tryptophan synthesized

C. when there is no tryptophan in the medium, transcription of the trp operon occurs at high levels

D. when there are high levels of tryptophan in the medium, transcription of the trp operon occurs at high levels

E. no transcription occurs under any nutritional circumstance because negative controls inhibit transcription

Answer 1

The terminating "hairpin" loop occurs in the tryptophan operon when ________.

B. sufficient tryptophan is present.----------------ANSWER

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2. When tryptophan is present in the medium and available to the bacterium, ________.

C. the repressor is bound to the operator, thus blocking transcription--ANSWER

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What occurs in a bacterium with respect to genetic regulation of the tryptophan operon?

C. when there is no tryptophan in the medium, transcription of the trp operon occurs at high levels

-----------ANSWE

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Microorganisms, for example, Escherichia coli (an inviting occupant of our gut) require amino acids to survive—in light of the fact that, similar to us, they have to fabricate proteins. One of the amino acids they need is tryptophan.

In the event that tryptophan is accessible in nature, E. coli will take it up and utilize it to fabricate proteins. Be that as it may, E. coli can likewise make their own tryptophan utilizing catalysts that are encoded by five qualities. These five qualities are situated alongside each other in what is known as the trp operon.

On the off chance that tryptophan is available in nature, then E. coli microscopic organisms don't have to combine it, so translation of the qualities in the trp operon is exchanged "off." When tryptophan accessibility is low, then again, the operon is exchanged "on," the qualities are interpreted, biosynthetic catalysts are made, and more tryptophan is produced.The trp operon incorporates five qualities that encode chemicals required for tryptophan biosynthesis, alongside a promoter (RNA polymerase restricting site) and an administrator (restricting site for a repressor protein). The qualities of the trp operon are interpreted as a solitary mRNA.This extend of DNA is perceived by an administrative protein known as the trp repressor. At the point when the repressor ties to the DNA of the administrator, it keeps the operon from being translated by physically impeding RNA polymerase, the interpretation enzyme.The trp repressor does not generally tie to DNA. Rather, it ties and pieces interpretation just when tryptophan is available. At the point when tryptophan is around, it appends to the repressor particles and changes their shape so they get to be dynamic. A little particle like trytophan, which switches a repressor into its dynamic state, is known as a corepressor.