Genetics: Analysis and Principles
6th Edition
ISBN: 9781259616020
Author: Robert J. Brooker Professor Dr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 14.3, Problem 3COMQ
Operons involved with the biosynthesis of molecules such as amino acids are most likely to be regulated in which of the following ways?
a. The product of the biosynthetic pathway represses transcription.
b. The product of the biosynthetic pathway activates transcription.
c. A precursor of the biosynthetic pathway represses transcription.
d. A precursor of the biosynthetic pathway activates transcription.
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Check out a sample textbook solutionStudents have asked these similar questions
Define the following in the context of operons:
a. positive control
b. give an example of an operon that is under positive control
c. negative control
d. give an example of an operon that is under negative control
e. repressor
f. give an example of a repressor molecule
g. activator
h. give an example of an activator
Control of the trp operon relies on which of the following:
a. High levels of tryptophan causing a pause (but not termination) in transcription
b. Low levels of tryptophan causing a pause (but not termination) in transcription
c. Allolactose binding to the inhibitor to prevent it from binding to the promoter
d. Tryptophan binding to the inhibitor to prevent it from binding to the promoter
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.
Chapter 14 Solutions
Genetics: Analysis and Principles
Ch. 14.1 - 1. A repressor is a __________ that _________...Ch. 14.1 - 2. Which of the following combinations will cause...Ch. 14.2 - 1. What is an operon?
a. A site in the DNA where...Ch. 14.2 - The binding of _______ to lac repressor causes lac...Ch. 14.2 - Prob. 3COMQCh. 14.2 - How does exposing an E. coli cell to glucose...Ch. 14.3 - When tryptophan binds to trp repressor, this...Ch. 14.3 - During attenuation, when tryptophan levels are...Ch. 14.3 - Operons involved with the biosynthesis of...Ch. 14.4 - 1. Translation can be regulated by
a....
Ch. 14.4 - Prob. 2COMQCh. 14.5 - 1. For a riboswitch that controls transcription,...Ch. 14 - 1. What is the difference between a constitutive...Ch. 14 - In general, why is it important to regulate genes?...Ch. 14 - Prob. 3CONQCh. 14 - Transcriptional regulation often involves a...Ch. 14 - An operon is repressible-a small effector molecule...Ch. 14 - Prob. 6CONQCh. 14 - 7. What is enzyme adaptation? From a genetic point...Ch. 14 - Prob. 8CONQCh. 14 - Prob. 9CONQCh. 14 - Prob. 10CONQCh. 14 - Mutations may have an effect on the expression of...Ch. 14 - 12. Would a mutation that inactivated lac...Ch. 14 - Prob. 13CONQCh. 14 - 14. As shown in Figure 14.12, four regions within...Ch. 14 - 15. As described in Chapter 13, enzymes known as...Ch. 14 - 16. The combination of a 3–4 stem-loop and a...Ch. 14 - 17. Mutations in tRNA genes can create tRNAs that...Ch. 14 - Prob. 18CONQCh. 14 - Prob. 19CONQCh. 14 - A species of bacteria can synthesize the amino...Ch. 14 - 21. Using three examples, describe how allosteric...Ch. 14 - How are the actions of lac repressor and trp...Ch. 14 - 23. Transcriptional repressor proteins (e.g., lac...Ch. 14 - Answer the following questions that pertain to the...Ch. 14 - Chapter 21 describes a blotting method known as...Ch. 14 - As described in experimental question E2 and also...Ch. 14 - Prob. 4EQCh. 14 - Explain how the data shown in Figure 14.9 indicate...Ch. 14 - Prob. 6EQCh. 14 - Lets suppose you have isolated a mutant strain of...Ch. 14 - Prob. 1QSDCCh. 14 - Prob. 2QSDC
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- A mutation in the operator region of the trp operon can prevent the trp repressor from binding to this operator. When these mutant cells are placed in a solution containing chicken broth, which of the following happens? a. Tryptophan would bind to the repressor. b. The Repressor would bind to the operator irrespective of the presence of amino acids in the environment. c. The transcription of the trip operon would be inhibited. d. The transcription of the repressor protein is inhibitedarrow_forwardThe regulation of the trp operon genes by the Trp repressor protein is an example of ______ gene regulation. A.)positive B.)negativearrow_forwardMutations may have an effect on the expression of the lac operon and the trp operon. Would the following mutations have a cis- or transeffect on the expression of the protein-encoding genes in the operon? A. A mutation in the operator site that prevents lac repressor from binding to it B. A mutation in the lacI gene that prevents lac repressor from binding to DNA C. A mutation in the trpL gene that prevents attenuationarrow_forward
- Which of the following is true about operons? A. Contains a cluster of genes transcribed as multiple mRNAs. B. Contains a cluster of genes transcribed as a single mRNA. C. They are commonly found in eukaryotes. D. Can only be regulated by gene activator proteins.arrow_forwardWhich of the following statements about gene regulation is false? a. An operon contains DNA sequences that regulates its own expression. b. The operator region can only be bound by an activator protein. c. Transcription factors can affect the binding of RNA polymerase to the promoter. d. A repressor is a transcription factor that hinders gene transcription.arrow_forwardOperons can not be: a. Negatively regulated b. Positively regulated c. Constitutive d. Inducible e. Repressible f. coding for related structural proteins g. Expressed by use of RNA polymerase h. Dependent on a promoter for expressionarrow_forward
- Study the depiction of the lac operon in Figure 11.2. Normally, the genes are turned off when lactose is not present. Lactose activates the genes, which code for enzymes that enable the cell to use lactose. Mutations can alter the function of this operon. Predict how the following mutations would affect the function of the operon in the presence and absence of lactose: a. mutation of regulatory gene; repressor will not bind to lactose b. mutation of operator; repressor will not bind to operator c. mutation of regulatory gene; repressor will not bind to operator d. mutation of promoter; RNA polymerase will not attach to promoterarrow_forwardIn lac operon, both gene A and gene B undergo a transcription process. Gene B can only undergo transcription in the presence of lactose and in the absence of glucose. The product of gene A is often altered by an inducer. Which of the following is true about genes A and B? Select one: a. Gene A= structural gene; Gene B= regulatory gene b. Gene A= regulatory gene; Gene B= structural gene c. Gene A= promoter gene; Gene B= operator gene d. Gene A= lacZ gene; Gene B= promoter genearrow_forwardcAMP binds to cAMP Receptor Protein (CRP), allowing CRP to bind to the promoter of the lac operon a) in positive gene regulation by increasing the transcription when glucose is absent and lactose is present b) in negative gene regulation by decreasing the transcription when glucose is absent and lactose is present c) in positive gene regulation by increasing the transcription when glucose is present and lactose is absent d) in negative gene regulation by decreasing the transcription when glucose is present and lactose is absentarrow_forward
- A mutation that inactivates the repressor gene of the lac operon results in (a) the continuous transcription of the structural genes (b) no transcription of the structural genes (c) the binding of the repressor to the operator (d) no production of RNA polymerase (e) no difference in the rate of transcriptionarrow_forwarda. What is the function of operons in bacterial gene regulation? b. Describe how a bacterial operon can be regulated by repressible proteins (such as the tryptophan operon). Include in your description both the “on” and “off” states of the operon. Key elements of your diagram should include: Co-repressor, Genes, mRNA, Operator, Operon, Promoter, Repressor, RNA polymerase.arrow_forwardIf the above gene is one of the three structural genes of the lac operon that codes for the protein/ enzyme responsible for breaking lactose into two molecules of simple sugars, what triggers the activation of this gene? a. Absence of Inhibitory protein b. Presence of lactose c. Absence of lactose d. Presence of Inhibitory protein e. Absence of Regulatory proteinarrow_forward
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