Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 16, Problem 28P
For each of the E. coli strains that follow, indicate the effect of the genotype on the expression of the trpE and 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 of tryptophan and are fully expressed in the absence of tryptophan.]
R = repressor gene; Rn product cannot bind tryptophan; R- product cannot bind operator
o = operator for the trp operon; o- cannot bind repressor
att = attenuator; att- is a deletion of the attenuator
P = promoter; P- is a deletion of the trp operon promoter
trpE− and trpC- are null (loss-of-function) mutations
| a. R+ P- o+ att+ trpE+ trpC+ |
| b. R- P+ o+ att+ trpE+ trpC+ |
| c. Rn P+ 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+ |
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For the lac genotypes shown in the following table, predict whether the structural genes (Z) are constitutive, permanently repressed, or inducible in the presence of lactose. Genotype Constitutive Repressed Inducible I+O+Z+ * I-O+Z+ I-OCZ+ I-OCZ+/F=O+ I+OCZ+/F=O+ ISO+Z+ ISO+Z+/F=I+
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 16 Solutions
Genetics: From Genes to Genomes
Ch. 16 - For each of the terms in the left column, choose...Ch. 16 - The following statement occurs early in this...Ch. 16 - One of the main lessons of this chapter is that...Ch. 16 - All mutations that abolish function of the Rho...Ch. 16 - The figure at the beginning of this chapter shows...Ch. 16 - The promoter of an operon is the site to which RNA...Ch. 16 - You are studying an operon containing three genes...Ch. 16 - You have isolated a protein that binds to DNA in...Ch. 16 - You have isolated two different mutants reg1 and...Ch. 16 - Bacteriophage , after infecting a cell, can...
Ch. 16 - Mutants were isolated in which the constitutive...Ch. 16 - Suppose you have six strains of E. coli. One is...Ch. 16 - The previous problem raises some interesting...Ch. 16 - For each of the E. coli strains containing the lac...Ch. 16 - For each of the following growth conditions, what...Ch. 16 - For each of the following mutant E. coli strains,...Ch. 16 - Maltose utilization in E. coli requires the...Ch. 16 - Seven E. coli mutants were isolated. The activity...Ch. 16 - Cells containing missense mutations in the crp...Ch. 16 - Six strains of E.coli mutants 16 that had one of...Ch. 16 - a. The original constitutive operator mutations in...Ch. 16 - In an effort to determine the location of an...Ch. 16 - Prob. 23PCh. 16 - The footprinting experiment described in Fig....Ch. 16 - Why is the trp attenuation mechanism unique to...Ch. 16 - a. How many ribosomes are required at a minimum...Ch. 16 - The following is a sequence of the leader region...Ch. 16 - For each of the E. coli strains that follow,...Ch. 16 - Prob. 29PCh. 16 - For each element in the list that follows,...Ch. 16 - Among the structurally simplest riboswitches are...Ch. 16 - Great variation exists in the mechanisms by which...Ch. 16 - Many genes whose expression is turned on by DNA...Ch. 16 - In 2005, Frederick Blattner and his colleagues...Ch. 16 - The E.coli MalT protein is a positive regulator of...Ch. 16 - Prob. 36PCh. 16 - Prob. 37PCh. 16 - Prob. 38PCh. 16 - Prob. 39PCh. 16 - Prob. 40PCh. 16 - Prob. 41PCh. 16 - The researchers who investigated bioluminescence...Ch. 16 - Prob. 43PCh. 16 - Quorum sensing controls the expression of...Ch. 16 - Scientists are currently screening a chemical...
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