Essentials of Genetics (9th Edition) - Standalone book
9th Edition
ISBN: 9780134047799
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 15, Problem 6PDQ
For the lac genotypes shown in the accompanying table, predict whether the structural gene (Z) is constitutive, permanently repressed, or inducible in the presence of lactose.
| Genotype | Constitutive | Repressed Inducible |
| I+O+Z+ I-O+Z+ I+OCZ+ |
X | |
| I-O+Z+/F'I+ I+OCZ+/F'OC ISO+Z+ ISO+Z+/F'I+ |
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
For each of the E. coli strains that follow, indicate theeffect of the genotype on the expression of the trpEand trpC genes in the presence or absence of tryptophan. [In the wild type (R+ P+ o+ att+ trpE+ trpC+),trpC and trpE are fully repressed in the presence oftryptophan and are fully expressed in the absence oftryptophan.]R = repressor gene; Rnproduct cannot bind tryptophan; R− product cannot bind operatoro = operator for the trp operon; o− cannot bind repressoratt = attenuator; att− is a deletion of the attenuatorP = promoter; P− is a deletion of the trp operonpromotertrpE− and trpC− are null (loss-of-function) mutationsa. R+ P− o+ att+ trpE+ trpC+b. R− P+ o+ att+ trpE+ trpC+c. RnP+ o+ att+ trpE+ trpC+d. R− P+ o+ att− trpE+ trpC+e. R+ P+ o− att+ trpE+ trpC−/R− P+ o+ att+trpE− trpC+f. R+ P− o+ att+ trpE+ trpC−/R− P+ o+ att+trpE− trpC+g. R+ P+ o− att− trpE+ trpC−/R− P+ o− att+trpE− trpC+
For the lac genotypes of Escherichia coli shown in the following Table 1, predict the expression
of beta-galactosidase (Z) and permease (Y) is inducible or noninducible or constitutive. Explain
your answer.
Table 1
Genotype
I-P+O+Z+Y+
(i)
(ii) I+P+OCZ+Y+
(iii) ISP+O+Z+Y+
(iv) I+P+O+Z+Y-//I+P-O+Z+Y+
(v) ISP+OcZ+Y+//I-P+O+Z+Y-
Condition
No lactose
No lactose
lactose
lactose
No lactose
The lac genotypes are as shown below:
P+OcZ-Y+A+// P¯O+Z+Y+A+
(i)
The lac operon consists of three structural genes, lacZ, lacY and lacA. Which
structural genes are involved in lactose metabolism? Explain.
(ii)
Draw and explain how lactose repress the gene expression in lac IS/I- heterozygote.
(iii)
What is the function of the promoter in the bacterial operon?
Chapter 15 Solutions
Essentials of Genetics (9th Edition) - Standalone book
Ch. 15 -
CASE STUDY | A mysterious muscular dystrophy
A...Ch. 15 -
CASE STUDY |A mysterious muscular dystrophy
A...Ch. 15 -
CASE STUDY |A mysterious muscular dystrophy
A...Ch. 15 -
HOW DO WE KNOW?
1. In this chapter, we have...Ch. 15 -
2. Review the Chapter Concepts list on p. 280....Ch. 15 - Describe which enzymes are required for lactose...Ch. 15 - Contrast positive versus negative regulation of...Ch. 15 -
5. Both attenuation and riboswitches rely on...Ch. 15 - For the lac genotypes shown in the accompanying...Ch. 15 -
7. For the genotypes and conditions (lactose...
Ch. 15 -
8. The locations of numerous lacI– and lacIs...Ch. 15 - Explain why catabolite repression is used in...Ch. 15 - Describe experiments that would confirm whether or...Ch. 15 - Predict the level of genetic activity of the lac...Ch. 15 - Predict the effect on the inducibility of the lac...Ch. 15 -
13. Describe the role of attenuation in the...Ch. 15 -
14. In a theoretical operon, genes A, B, C, and D...Ch. 15 - A bacterial operon is responsible for production...Ch. 15 - A marine bacterium is isolated and is shown to...Ch. 15 -
17. Why is gene regulation more complex in a...Ch. 15 -
18. List and define the levels of eukaryotic gene...Ch. 15 -
19. Distinguish between the cis-acting regulatory...Ch. 15 - Prob. 20PDQCh. 15 - Compare the control of gene regulation in...Ch. 15 - Many eukaryotic promoter regions contain CAAT...Ch. 15 -
23. What is RNA-induced gene silencing in...Ch. 15 - Although it is customary to consider...Ch. 15 - DNA methylation is commonly associated with a...Ch. 15 - The interphase nucleus appears to be a highly...Ch. 15 - It has been estimated that at least two-thirds of...
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
- O The lac operon in E.coli encodes enzymes necessary for the breakdown of lactose. For each enzyme (lac Z and lac Y), indicate with a + or-whether or not it is made when there is no lactose or when there is lactose. B-galactosidase (lac Z) No Lactose Permease (lac Y) Lactose Lactose No Lactose Genotype PP0 Z Y/I P*O*Z•Y* I'POCZ Y*/I P* O©Z*Y° P O Z'Y/I P'OʻZ'Y* PP O ZY*/IP*O*Z*Y* IP OCZ Y /I P*O*Z•Y* IPO ZY*/I* P*O©Z*Y• I'PO*Z Y*/IP'O*Z*Y°arrow_forwardFor each of the E. coli strains containing lac operon alleles listed, indicate whether the strain is inducible, constitutive, or unable to express beta-galactosidase and permease. (P+ and P- are functional and nonfunctional promoters, respectively) I+ P+ o+ Z- Y+ / I+ P+ oc Z+ Y+ I+ P+ o+ Z+ Y+ / I- P+ oc Z+ Y- I+ P+ o+ Z- Y+ / I- P+ oc Z+ Y- I- P- o+ Z+ Y- / I+ P+ oc Z- Y+ IS P+ o+ Z+ Y+ / I- P+ o+ Z+ Y-arrow_forwardFor the given genotypes (associated with the lac operon in E. coli), indicate with a "+" or "-" whether functional B - galactosidase would be expected to be produced in the indicated conditions, assuming low glucose levels. B - galactosidase production Genotype No lactose With lactose a) I- O+ Z+ / F' I+ O+ Z+ b) IS O+ Z+/ F' I+ O+ Z+arrow_forward
- Given the following Western blot results showing levels of proteins over time in three yeast cell extracts after the induction of high level expression of the CDH1 protein. WT GAL-CDH1 GAL-CDH1, cdc23-1 0 30 60 120 0 30 60 120 0 30 60 120 Time (min) - Pds1 - Clb2 - Ase1 - Kar2 Note: The GAL-CDH1 indicates that the yeast strain contains a transgenic cdh1 gene under the control of the GAL promoter. This means that the researcher can control expression of that cdh1 gene. In these three experiments (three yeast strains), time 0 is the point at which GAL- controlled genes begin to get expressed (WT lacks transgenes). In this experiment, four proteins are being probed for in three different yeast strains (1. wild-type, 2. a strain containing the cdh1 gene under GAL control (see note), and 3. the GAL-CDH1 strain that is also harboring a cdc23 loss of function allele (allele 1), which is a component of the A The upper (larger) band in the Ase1 lanes is non-specific background band; disregard…arrow_forwardDescribe how polymorphisms is found at 13910-C/T and 22018-G/A in the regulatory area of the lactase gene (LCT). And elaborate the mechanism for two polymorphisms causing mutation from 13910-C/T and 22018-G/A to 13910-C/C or 22018-G/G variants in lactase intolerance disorder. also, how LCT gene is corelated to lactase intolerance disorder?arrow_forwardGiven the following Western blot results showing levels of proteins over time in three yeast cell extracts after the induction of high level expression of the CDH1 protein. WT GAL-CDH1 GAL-CDH1, cdc23-1 0 30 60 120 0 30 60 120 0 30 60 120 Time (min) | Pds1 - Clb2 - Ase1 - Kar2 Note: The GAL-CDH1 indicates that the yeast strain contains a transgenic cdh1 gene under the control of the GAL promoter. This means that the researcher can control expression of that cdh1 gene. In these three experiments (three yeast strains), time O is the point at which GAL- controlled genes begin to get expressed (WT lacks transgenes). which is a component of the A In this experiment, four proteins are being probed for in three different yeast strains (1. wild-type, 2. a strain containing the cdh1 gene under GAL control (see note), and 3. the GAL-CDH1 strain that is also harboring a cdc23 loss of function allele (allele The upper (larger) band in the Ase1 lanes is non-specific background band; disregard it.…arrow_forward
- A number of mutations affect the expression of the lac operon in E. coli. The genotypes of several E. coli strains are shown below. ("+" indicates a wild-type gene with normal function and "-" indicates a loss-of-function allele.) Please predict which of the following strains would have the lowest beta-galactosidase enzyme activity, when grown in the lactose medium. OF POZY Ort Ptot Z¹ Yt Ort p²o+z¹Y+ Orpt ot ztyarrow_forwardIn studies of the amino acid sequence of wild-type and mutant forms of tryptophan synthetase in E. coli, the following changes have been observed: Determine a set of triplet codes in which only a single-nucleotide change produces each amino acid change.arrow_forwardBased on the partial diploid sketched shown in Figure 3, where cross-hatched rectangles and the red bar indicate mutations that inactivate that particular genetic element of the operon, state if expression of Lacl (Lac repressor) and LacZ (Beta-Galactosidase) is (select one of the options below for each genetic element and briefly justify your answer): constitutively ON (in the presence/absence of lactose) constitutively OFF (in the presence/absence of lactose) • inducible by lactose • not enough information given to conclude • none of the above FIGURE 3: lacl laco lacz- lacY lacl laco lacz lacYarrow_forward
- The following shows the genotype of a partial diploid bacterial cell - where one chromosomal region containing the lac operon in E,coli is given, and the other fragment is from a plasmid carrying another lac operon from another source. The two are separated by a slash (/). The possible answers indicate with a ʺ+ʺ or a ʺ-ʺ whether β-galactosidase would be expected to be produced at induced levels under two circumstances: 1) first in the absence of lactose and 2) second in the presence of lactose. (Assume that glucose is not present in the medium.)Genotype F: I+ Oc Z-/ Fʹ I- O+ Z+ KEY:I+ = wild-type repressorI- = mutant repressor (unable to bind to the operator)Is = mutant repressor (insensitive to lactose)O+ = wild-type operatorOc = constitutive operator (insensitive to repressor)arrow_forwardA number of mutations affect the expression of the lac operon in E. coli. The genotypes of several E. coli strains are shown below. ("+" indicates a wild-type gene with normal function and "-" indicates a loss-of-function allele.) Please predict which of the following strains would have the lowest beta-galactosidase enzyme activity, when grown in the lactose medium. Orpt o* z* r* Orpt ot z* Y OrptoztY Orrotzr OrPotz*Yarrow_forwardWhy is it adaptive for the structural genes for using lactose to be under the control of a single promoter (i.e., synthesize a polycistronic message rather than three monocistronic messages)? a. For efficient absorption and catabolism of lactose, structural genes send a single signal. This is why polycistronic message is favored more than the monocistronic message since the former involves transmission of numerous messages in initiation and termination. b. Polycistronic message is favored more than the monocistronic message. c. Polycistronic message is favored more than the monocistronic message since the former involves transmission of numerous messages in initiation and termination. d. For an efficient absorption and catabolism of lactose, structural genes send a single signal only. e. Polycistronic message is favored more than the monocistronic message since the former involves transmission of single message in initiation and termination.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSON
Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax
Anatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:9780815344322
Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education
QCE Biology: Introduction to Gene Expression; Author: Atomi;https://www.youtube.com/watch?v=a7hydUtCIJk;License: Standard YouTube License, CC-BY