You isolate 20 different OC mutant strains that are wild type for all other components of the Lac Operon. You observe that when grown on lactose all of the strains exhibit a relative B-gal concentration of 100. When each strain is grown on glucose they all exhibit constitutive expression of B-gal, but the different strains exhibit different Bgal concentrations that range from 20 to 100. Which of the following could account for these observations?
a) the OC mutant strains each produces a different form of repressor protein
b) the OC mutant strains each exhibits different degrees of binding to allolactose
c) the OC mutant strains exhibit different degrees of binding of RNA polymerase
d) the OC mutant strains each exhibits a different degree of binding of the repressor protein e) none of the above could possibly account for the differences among strains
The correct option is
c) the OC mutant strains exhibit different degrees of binding of RNA polymerase
You isolate 20 different OC mutant strains that are wild type for all other components of...
Imagine you are carrying out research on the lac
operon. You isolate six mutations in the lac operon by
measuring the amount of beta-galactosidase made in mutant cell line
under three different conditions: no lactose/no glucose; lactose
only; and lactose/glucose. Your results are shown in the table.
Strain
No Lactose, No Glucose
Lactose
Lactose, Glucose
Wild-type
None
High
Low
Mutant 1
None
None
None
Mutant 2
None
None
None
Mutant 3
None
Low
Low
Mutant 4
None
Low
Low
Mutant...
The lac operon contains a DNA sequence known as the lac promoter (P or P+ for wild type; P– for mutant (RNA polymerase does not bind)) that serves as the RNA polymerase binding site. The lac operon also contains a DNA sequence known as the Lac operator (O or O+ for wild type; O– or Oc for mutant (lac repressor cannot bind)) which is the binding site for lac repressor. The lac repressor, a protein, is encoded by the lac...
The genotypes of the lac operon of several haploid and
partial diploid E. coli strains are given. For each genotype,
indicate the status of B-galactosidase synthesis as either Yes or
No. Assume that no glucose is present and cAMP is rich in the
growth medium.
• Oc is a mutant operator that cannot be bound
by the wild type repressor protein.
• Is is a mutant of repressor gene and cannot
bind to operator
Haploid Partial Diploid IOZY IOCZY ISOZY...
You are asked to develop a demonstration to show how the
lac operon works. You decide to use X-gal and IPTG to
determine if the enzyme ?-galactosidase is active. X-gal is a
lactose analog that turns blue when metabolized by ?-galactosidase,
but it does not induce the lac operon. IPTG is an inducer
of the lac operon, but is not metabolized by ?-galactosidase.
a. (2pts) Which of the following would you expect to bind to
?-galactosidase. Circle all that apply....
There are two different strains of E. coli. One type is a wild type and the other is a lac operon mutant. The lac operon wild type has the genotype: I+P+O+Z+Y+A+ What is a silent mutation? What would be the result for the lac operon genes?
QUESTION 8 The following situations (1-4) involve different types of gene regulation in prokaryotic cells as shown. OFF and ON reter to whether the gene is transcribed or not. Draw clearly-labelled regulatory proteins and effector molecules in each diagram to explain how the regulation works in each case. The first one has been done for you as an example a) (6 marks) Type of Regulation Regulatory protein effector molecule 1 DNA X negative inducible OFF ON 2 negative repressible DNA...
2. Suppose you have six strains of E. coli. One is wild type, and each of the other five has a single one of the following mutations: lacZ, lacY, laď·0; and lach. For each of these six strains, describe the phenotype you would observe using the following assays. Explain your answers. [Notes: (1) IPTG is a colorless synthetic molecule that acts as an inducer of lac operon expression but cannot serve as a carbon source for bacterial growth because it...
In this problem you will explore how to solve problems involving partial diploid lac operon bacterial strains. Bacterial strains that are "partially diploid" have two copies of the lac operon because they aquired a plasmid carrying just the lac operon region. One copy of the lac operon region is on the recipient's bacterial chromosome, and the other copy is on the P plasmid that was introduced into the cell by conjugation. Partial diploid genotypes are written with the P segment...
all them please
Question 23 (1 point) The A and B alleles in ABO blood types can give rise to an individual that is blog type AB. This specific blood type is an example of: A) multiple alleles B) epistasis C) codominance D) partial dominance Imagine the gene encoding the lac repressor was mutated so that lactose (more technically allolactose) no longer bound to the repressor. However, the lac repressor was still capable of binding DNA at the operator sequence....
As a student project, you have isolated six new mutant strains
of E. coli with altered behavior of the lactose operon. The strains
are listed in the table below, together with their phenotypes (with
regard to significant ?-galactosidase synthesis) in three specific
situations.
Columns 1 and 2 present the phenotypes of each mutant haploid
strain. In column 1, the mutant is in an otherwise wild-type
genome. In column 2, the genome also carries a nonsense-suppressor
mutation (that is not present...