Biology: Concepts and Investigations
5th Edition
ISBN: 9781260259049
Author: Hoefnagels
Publisher: MCG
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Textbook Question
Chapter 7, Problem 7MCQ
How does the lac operon regulate lactose digestion in bacteria?
a. The repressor protein becomes a lactose-digesting enzyme only when lactose is present.
b. The repressor protein binds to the lac operon when lactose is present, blocking transcription.
c. When lactose is present, it binds to the operator region of the lac operon, activating transcription of the repressor protein gene.
d. The repressor protein falls off the lac operon when lactose is present, and lactose-digesting genes are expressed.
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How does the lac operon regulate lactose digestion in bacteria?a. The repressor protein becomes a lactose-digesting enzyme onlywhen lactose is present.b. The repressor protein binds to the lac operon when lactose ispresent, blocking transcription.c. When lactose is present, it binds to the operator region of the lacoperon, activating transcription of the repressor protein gene.d. The repressor protein falls off the lac operon when lactose ispresent, and lactose-digesting genes are expressed.
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 inhibited
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?
Chapter 7 Solutions
Biology: Concepts and Investigations
Ch. 7.1 - How did Griffiths research, coupled with the work...Ch. 7.1 - How did the Hershey-Chase blender experiments...Ch. 7.2 - What are the components of DNA and its...Ch. 7.2 - What evidence enabled Watson and Crick to decipher...Ch. 7.2 - Prob. 3MCCh. 7.3 - What is the relationship between a gene and a...Ch. 7.3 - Prob. 2MCCh. 7.3 - What are the three types of RNA, and how does each...Ch. 7.4 - What happens during each stage of transcription?Ch. 7.4 - Where in the cell does transcription occur?
Ch. 7.4 - What is the role of RNA polymerase in...Ch. 7.4 - What are the roles of the promoter and terminator...Ch. 7.4 - How is mRNA modified before it leaves the nucleus...Ch. 7.5 - How did researchers determine that the genetic...Ch. 7.5 - What happens in each stage of translation?Ch. 7.5 - Where in the cell does translation occur?Ch. 7.5 - How are polypeptides modified after translation?Ch. 7.6 - What are some reasons that cells regulate gene...Ch. 7.6 - Prob. 2MCCh. 7.6 - Prob. 3MCCh. 7.6 - Prob. 4MCCh. 7.7 - What is a mutation?Ch. 7.7 - What are the types of mutations, and how does each...Ch. 7.7 - Prob. 3MCCh. 7.7 - Prob. 4MCCh. 7.7 - How are mutations important?Ch. 7.8 - What question about the FOXP2 gene were the...Ch. 7.8 - What insights could scientists gain by...Ch. 7 - A nucleotide is composed of all of the following...Ch. 7 - Prob. 2MCQCh. 7 - Transcription copies a _______ to a complementary...Ch. 7 - Choose the DNA sequence from which this mRNA...Ch. 7 - Prob. 5MCQCh. 7 - Prob. 6MCQCh. 7 - How does the lac operon regulate lactose digestion...Ch. 7 - Prob. 8MCQCh. 7 - Prob. 9MCQCh. 7 - Prob. 10MCQCh. 7 - Explain how Griffiths experiment and Avery,...Ch. 7 - Prob. 2WIOCh. 7 - Prob. 3WIOCh. 7 - Put the following in order from smallest to...Ch. 7 - Prob. 5WIOCh. 7 - List the three major types of RNA and their...Ch. 7 - Some people compare DNA to a blueprint stored in...Ch. 7 - Prob. 8WIOCh. 7 - Prob. 9WIOCh. 7 - If a protein is 1259 amino acids long, what is the...Ch. 7 - Prob. 11WIOCh. 7 - The roundworm C. elegans has 556 cells when it...Ch. 7 - A protein-encoding region of a gene has the...Ch. 7 - Explain how a mutation in a protein-encoding gene,...Ch. 7 - Refer to the figure to answer these questions: a....Ch. 7 - Describe the mutation shown in figure 7.27 and...Ch. 7 - Prob. 17WIOCh. 7 - Parkinson disease causes rigidity, tremors, and...Ch. 7 - Refer to figure 7.28 and the chapter con tent to...Ch. 7 - Prob. 2PITCh. 7 - Prob. 3PITCh. 7 - Prob. 4PIT
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- If lactose isn't present in the environment of an E. coli, what is the state of the lac operon? O a. It is "on" (high transcription) because will glucose will still be present, so the operon's products will be needed. O b. It is "on" (high transcription) because CAP will be bound to the promoter O c. It is "off" (no transcription) because RNA polymerase will be inactivated d. It is "off" (no transcription) and the repressor will be bound to the operatorarrow_forwardWhat is the role of a substrate that controls a repressible operon? a. increase the production of inactive repressor proteins b. bind to the repressor protein and activate it c. bind to the repressor protein and deactivate it d. bind to the promoter region and decrease the affinity of RNA polymerase for the promoterarrow_forwardWhen iron is scarce, some bacteria can stop synthesis of all enzymes that require iron (Fe3+), such as superoxide dismutase (SOD). Which of the following accurately describes a mechanism for this regulation? Mark all that apply. A. Regulation occurs by an inducible operon B. When absent, the lack of iron causes the repressor to deactivate and block the promoter region for these genes C. Regulation occurs by a repressible operon D. When present, iron binds and activates the repressor proteinarrow_forward
- Answer this 3 part question: (MC) What is the function of lactose in regulation of the lac operon? 1. activates a repressor protein 2. activates an activator protein 3. inactivates a repressor protein 4. inactivates an activator protein Consider a bacterial strain with a lac operon Р. О Y A a) Mention which parts of the DNA region shown in the diagram encode for • Enzyme proteins? • Operator • Promoter • Repressor gene b) Where would the lac repressor be bound in a E. coli cell that is growing in ( • high lactose? No lactosearrow_forwardControl 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 promoterarrow_forwardIf CAP is bound to the Promoter of the Lac Operon and the repressor protein is not bound to the operator, which of the following is true: a.Glucose Levels are low & Lactose is absent b.Glucose is absent & Lactose is present c.cAMP is low & Lactose is Absent d.Glucose and Lactose are Present e.cAMP is low & Lactose is presentarrow_forward
- Mutations in the genes of the lac operon might affect the regulation of β-galactosidase synthesis. For each mutation listed below, indicating whether β-galactosidase would be regulated normally, always ON or always OFF. a. Mutation in operator site prevents repressor binding b. Mutation in lacIgene prevents repressor from binding operator c. Mutation in lacIgene prevents repressor from binding allolactose d. Nonsense mutation in lacZgenerearrow_forwardIn the lac operon, the lac genes are transcribed in the presence of lactose because a RNA polymerase binds to the operator b The repressor can not bind the promoter c Production of the repressor protein is inducible d The inducer binds to the repressor e The inducer binds to the operatorarrow_forwardIn the lac operon, how would gene expression be affected if each one of the following segments was missing? A. lac operon promoter B. Operator site C. lacA genearrow_forward
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