Biology
5th Edition
ISBN: 9781260487947
Author: BROOKER
Publisher: MCG
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 14.2, Problem 2EQ
CoreSKILL » What was the eventual hypothesis proposed by the researchers to explain the function of the lacI gene and the regulation of the lac operon?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Read aloud
V Draw
Highlight
2. You are studying the regulation of the lactose operon in Escherichia coli, by
measuring expression of the lacZ gene (i.e production of beta-galactosidase).
(a) You identify several loss-of-function mutations in which lacZ is never
expressed, in the presence and absence of glucose and lactose. What
components of the lac operon could be mutated to produce this phenotype?
List all possibilities.
(b) You identify another loss-of-function mutation with the following expression
pattern:
Media
+ glucose - lactose
+ glucose +lactose
- glucose - lactose
- glucose + lactose
lacZ expression
Low
Low
High
High
What components of the lac operon could be mutated to produce this
phenotype? List all possibilities.
How might a frame shift mutation in the lacy region influence the phenotype of
this bacteria when glucose is abundant in the cell?
• How would a missense mutation in lacl alter the amount of B-Galactosidase
present in the cell?
●
If wild type E. coli were exposed to a growth medium containing glucose,
lactose and cyclic adenosine monophosphate, what would happen to the lac
operon?
Repressor gene
lacl
Regulatory region
Promoter-Operator B-Galactosidase gene
P
O
lacz
Structural genes
Permease gene
lac Operon
lacy
Transacetylase gene
lacA
. Recall that the trp operon has a special leader sequence (trpL) between the operator and the structural genes that offers attenuation as a mechanism for regulation of gene expression.
(A) Draw a diagram of a trpL region of the operon when tryptophan is abundant in the cell.Label the following features: the DNA, 5’ and 3’ polarity of the RNA, the regions 1, 2, 3,and 4 and poly-U of the RNA, the pair of Trp codons (UGG), the ribosome, and RNA-Pol,along with any stem-loop structure that would form under these conditions
(B) In the above example, will the rest of the trp operon genes be expressed? Briefly describe your reasoning why or why not
(C) The trp codons in region 1 of the trpL gene have mutated to cysteines (UGG to UGC). What will be the effect on attenuation gene regulation of the trp operon? Brieflyexplain your reasoning.
Chapter 14 Solutions
Biology
Ch. 14.1 - Prob. 1CCCh. 14.2 - Which genes are under the control of the lac...Ch. 14.2 - With regard to regulatory proteins and small...Ch. 14.2 - What were the key observations made by Jacob,...Ch. 14.2 - CoreSKILL What was the eventual hypothesis...Ch. 14.2 - Prob. 3EQCh. 14.2 - Core Skill: Connections Look back at Fig 9.12....Ch. 14.2 - What are the advantages of having both an...Ch. 14.2 - Prob. 2CSCh. 14.3 - Prob. 1CC
Ch. 14.4 - What are the two opposing effects that histone...Ch. 14.4 - Prob. 1CSCh. 14.5 - Prob. 1CCCh. 14.5 - Prob. 2CCCh. 14 - Prob. 1TYCh. 14 - Prob. 2TYCh. 14 - Transcription factors that bind to DNA and...Ch. 14 - Prob. 4TYCh. 14 - For the lac operon, what would be the expected...Ch. 14 - Prob. 6TYCh. 14 - The trp operon is considered _____ blank operon...Ch. 14 - Prob. 8TYCh. 14 - Prob. 9TYCh. 14 - _____ blank refers to the process that allows a...Ch. 14 - Prob. 1CQCh. 14 - Transcriptional regulation often involves a...Ch. 14 - Prob. 3CQCh. 14 - Discuss the advantages and disadvantages of...Ch. 14 - Discuss the advantages and disadvantages of...
Additional Science Textbook Solutions
Find more solutions based on key concepts
Why is it necessary to be in a pressurized cabin when flying at 30,000 feet?
Anatomy & Physiology (6th Edition)
11. In the early 1800s, French naturalist Jean Baptiste Lamarck suggested that the best explanation for the rel...
Campbell Biology: Concepts & Connections (9th Edition)
Jellyfish Lake, located on the Pacific island of Palau, is home to millions of jellyfish. Many years ago, sea l...
BIOLOGY:THE ESSENTIALS (LL) W/CONNECT
The appearance of glucose in the urine a. occurs normally. b. indicates the presence of kidney disease. c. occu...
Human Physiology
Some species of bacteria that live at the surface of sediment on the bottom of lakes are capable of using eithe...
Biology: Life on Earth with Physiology (11th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- What structural features does the trp operon share with the lac operon?arrow_forwardExplain how HOTAIR plays a role in the transcriptional regulationof particular genes.arrow_forwardQ1. Bioluminescence is emitted by the marine bacterium Vibrio fischeri in response to the concentration of a chemical signal. The luxCDABEG genes form part of an operon that encodes all of the structural components necessary for light production. At high cell density, the concentration of the inducer increases and can bind to LuxR protein which then activates transcription of the operon. What kind of operon is the Lux operon? [Positive Inducible, Positive Repressible, Negative Inducible, Negative Repressible?] Q2. A population of bacteria has a Lux operon that produces bioluminesence via an autoinducer that activates a transcription factor. You grow a flask of cells that have a loss-of-function mutation in the gene that encodes the enzyme that produces an autoinducer. What is the predicted bioluminesence in this population at high and low density?arrow_forward
- E30. An electrophoretic mobility shift assay can be used to study the binding of proteins to a segment of DNA. In the experiment shown here, an EMSA was used to examine the requirements for the bind- ing of RNA polymerase II (from eukaryotic cells) to the promoter of a protein-encoding gene. The assembly of general transcription factors and RNA polymerase II at the core promoter is described in Chapter 12 (Figure 12.14). In this experiment, the segment of DNA containing a promoter sequence was 1100 bp in length. The fragment was mixed with various combinations of proteins and then subjected to an EMSA. Lane 1: No proteins added Lane 2: TFID Lane 3: TFIIB Lane 4: RNA polymerase I| Lane 5: TFID + TFIIB Lane 6: TFID + RNA 1 2 4 5 6 polymerase II| Lane 7: TFIID + TFIIB + RNA polymerase I| 1100 bp Explain which proteins (TFIID, TFIIB, or RNA polymerase II) are able to bind to this DNA fragment by themselves. Which transcrip- tion factors (i.e., TFIID or TFIIB) are needed for the binding of…arrow_forwardPlz answer ASAP. I will thumb up You are studying the regulation of the lactose operon in Escherichia coli, by measuring expression of the lacZ gene (i.e production of beta-galactosidase).(a) You identify several loss-of-function mutations in which lacZ is never expressed, in the presence and absence of glucose and lactose. What components of the lac operon could be mutated to produce this phenotype? List all possibilities.arrow_forwarda. The original constitutive operator mutations in thelac operon were all base changes in o1. Why doyou think mutations in o2 or o3 were not isolated inthese screens?b. Explain how a mutagen that causes small insertions could produce an ocmutation.c. Would a strain with one of the ocmutations described in part (b) and also a lacIS mutation be ableto make β-galactosidase either in the presence orabsence of inducer? Explainarrow_forward
- What was the eventual hypothesis proposed bythe researchers to explain the function of the lacI gene and theregulation of the lac operon?arrow_forwardPlease answer fast Explain how you would go about developing new ribozymes capable of targeting new sequences and that can be controlled using effector molecules of your choosing.arrow_forwardAnswer as Directed. Below is the model of a lac operon. lac I lac Z с promoter operator lac Y lac A DNA +1 1. What are structural genes? Are the lac structural genes transcribed in the absence of lactose? 2. What is the role of the promoter and operator sites in the operon? 3. Is the repressor protein bound to the operator site in the absence of lactose? In its absence? 4. Under what nutritional circumstances (high or low glucose) is CAP bound to cAMP? 5. In the absence of lactose and the presence of glucose in the bacterial growth media, what proteins are bound to the lac control region? Is the operon being transcribed then? 6. In the presence of lactose and the presence of glucose in the bacterial growth media, what proteins are bound to the lac regulatory region? Is the operon being transcribed then? 7. In the presence of lactose and the absence of glucose in the bacterial growth media, what proteins are bound to the lac control region? 8. Why is it adaptive for a bacterium to not…arrow_forward
- Cell and Molecular Biology Subject: 1. Explain how the actions of the lac operon are different from the trp operon. 2. Why is it important for a multicellular organism to be able to turn on only some of its genes in any particular tissue or cell type?arrow_forwardQ1 There are similarities and differences during regulation of gene expression in both prokaryotes and eukaryotes. Promoters, transcription factors and RNA polymerase are essential elements in transcription but their properties and function may differ. b) Hypothesize the transcription of eukaryotic genes using prokaryotic promoter with further explanation.arrow_forward97Which of the following is examples of a transposable element found in bacteria? (multiple choice questions)A.IS903b.Tn5c.IS1D.Xis 98What is the key component of the catalytic site of the spliceosome? (multiple choice questions)A.DNAb.ribosomesc.proteinD.RNA 99Which antibiotic can binds to RNA polymerase and blocks an early step in RNA synthesis?A.Ampicillinb.Chloramphenicolc.RimantidineD.None of the above 100All tRNA molecules have poly (A) tails at their 3' end. Yesornoarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning
Biology (MindTap Course List)
Biology
ISBN:9781337392938
Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Publisher:Cengage Learning
Bacterial Genomics and Metagenomics; Author: Quadram Institute;https://www.youtube.com/watch?v=_6IdVTAFXoU;License: Standard youtube license