Homework Answers
Answer 29:
Tryptophan operon functions to synthesize the amino acid 'tryptophan'. This operon is a "negatively controlled repressible operon" which means that this operon in inhibited whenever the effector molecule (tryptophan) is present in the growth medium. The working of this operon can be briefly understood as :
- When tryptophan is not present in the medium, repressor molecule is inactive and thus transcription of tryptophan operon is activated.
- On the other hand, when tryptophan is present in the medium, the repressor gets activated and transcription of tryptophan is deactivated.
Tryptophan acts as a co-repressor molecule, because the repressor for tryptophan operon is inactive when alone. The repressor undergoes a conformational change upon binding to tryptophan and gets activated.
The inactive form of repressor (aporepressor) cannot bind to operator region, whereas the active repressor (bound to tryptophan) can bind to the operator region.
Binding of repressor to operator doesn't allow RNA polymerase enzyme to bind the promoter site and thus transcription of tryptophan operon genes is blocked. (Promoter and operator site overlap in trp operon).
Hence, the correct statement should be:
(A) It is deactivated whenever tryptophan is added to the growth medium.
Add Answer to:
23) The tryptophan operon in some bacteria is a repressible operon. Which of the following statements...
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Under which of the following conditions will transcription of the lac operon occur when the bacteria...
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1) Which of the following conditions is most likely to cause the lactose operon to be...
1) Which of the following conditions is most likely to cause the lactose operon to be transcribed? A) There is more glucose in the cell than lactose. B) There is glucose but no lactose in the cell. C) The cyclic AMP and lactose levels are both high within the cell. D) The CAMP level is high and the lactose level is low. 2) How does the transcription of structural genes in an inducible operon occur? A) It occurs continuously in...
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Which of the following statements about Huntington's is true? You can retry this question, the average...
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Which of the following statements is correct concerning operon gene control? Positive control requires an activator...
Which of the following statements is correct concerning operon gene control? Positive control requires an activator protein to stimulate transcription of the structural genes within an operon. In negative control, a repressor protein inhibits or turns off transcription of the structural genes within the operon. An inducible operon normally is not transcribed. It requires an inducer molecule to stimulate transcription either by inactivating a repressor protein in a negative inducible operon or by stimulating the activator protein in a positive...
for 1-5 define those The Lac operon is an inducible set of genes found in bacteria...
for
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The Lac operon is an inducible set of genes found in bacteria cells that helps the bacteria to metabolize the disaccharide lactose. When it is turned on it produces proteins that pump lactose into the bacteria cell and break it down into glucose and galactose, which can then be used by the bacteria as a source of energy The two figures below show the Lac Operon along with the lacl gene (which regulates the Lac operon...
Which of the following is NOT expected when a eukaryotic cell is deprived from Oxygen? Question...
Which of the following is NOT expected when a eukaryotic cell is deprived from Oxygen? Question 40 Not yet answered Points out of 2.50 P Flag question Select one: O a. The formation of CO2 from cell respiration stops o b. Reduction of the production of ATP by substrate level phosphorylation in the mitochondria c. All listed events are expected in a eukaryotic cell deprived of oxygen O d. The cell reduces pyruvate (fermentation) to allow the ETC to continue...
If we placed a bacterium into a medium that contained neither lactose nor glucose (let's give...
If we placed a bacterium into a medium that contained neither lactose nor glucose (let's give them arabinose instead), what will be the level of transcription from the lac operon? O A OFF (fully repressed, but not activated) O B BASAL (neither repressed nor activated) O C HIGH (not repressed, but activated) O D OFF (both repressed and activated, but the repressor "wins") Under what conditions do we get maximum transcription from the lac operon? O A When both glucose...
Consider what you know about the lac operon, and predict whether the repressor and the activator...
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1) Which of the following conditions is most likely to cause the lactose operon to be transcribed? A) There is more glucose in the cell than lactose. B) There is glucose but no lactose in the cell. C) The cyclic AMP and lactose levels are both high within the cell. D) The CAMP level is high and the lactose level is low. 2) How does the transcription of structural genes in an inducible operon occur? A) It occurs continuously in...
gene regulation of bacteria operon systems. Protected View . Saved to this PG References Mailings Review View Help Tell me what you want to do ernet can contain viruses. Unless you need to edit, it's safe to stay in Protected View Enable Editing 5. What happens if lactose levels are low? Put the following list in order (1-5). RNA polymerase is blocked from transcribing the genes for the lactose metabolizing enzymes When RNA polymerase binds to the promoter, it cannot...
Which of the following statements about Huntington's is true? You can retry this question, the average of your two answers is recorded. You should see feedback if you get a question wrong. O a. The mutated allele(s) has/have lost the function of keeping brain cells healthy, and is/are therefor a dominant disease O b. Huntington is a very rare and therfor recessive. c. Huntington strikes people after reproductive age and is therefor dominant. d. The mutated allele(s) has/have gained the...
Which of the following statements is correct concerning operon gene control? Positive control requires an activator protein to stimulate transcription of the structural genes within an operon. In negative control, a repressor protein inhibits or turns off transcription of the structural genes within the operon. An inducible operon normally is not transcribed. It requires an inducer molecule to stimulate transcription either by inactivating a repressor protein in a negative inducible operon or by stimulating the activator protein in a positive...
for
1-5 define those
The Lac operon is an inducible set of genes found in bacteria cells that helps the bacteria to metabolize the disaccharide lactose. When it is turned on it produces proteins that pump lactose into the bacteria cell and break it down into glucose and galactose, which can then be used by the bacteria as a source of energy The two figures below show the Lac Operon along with the lacl gene (which regulates the Lac operon...
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If we placed a bacterium into a medium that contained neither lactose nor glucose (let's give them arabinose instead), what will be the level of transcription from the lac operon? O A OFF (fully repressed, but not activated) O B BASAL (neither repressed nor activated) O C HIGH (not repressed, but activated) O D OFF (both repressed and activated, but the repressor "wins") Under what conditions do we get maximum transcription from the lac operon? O A When both glucose...
Consider what you know about the lac operon, and predict whether the repressor and the activator is active (able to bind to DNA) or inactive (unable to bind to DNA), and the level of transcription in the following scenarios. Options for transcription levels include high, medium, leaky and off. a. When lactose is present but glucose is not, the repressor is and the activator is leading to levels of transcription. and the activator is b. When lactose and glucose are...
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