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Assertion (A) : Each operon has its specific operator and specific repressor.

Reason (R) : Lac operator is present only in the Lac operon and it interacts specifically with Lac repressor only.

The correct option among the following is:

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Important Questions on Molecular Basis of Inheritance

EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression

Given the diagram of the lac operon showing an operon of inducible enzymes. Identify components and enzymes (A,B,C,D and E) ?

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EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Expression of gene regulation results in:
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Identify the incorrect phenomenon expressed by a bacterium grown in a medium lacking lactose.
I) Initiates beta-galactosidase activity
II) Bacteria does not produce galactose and glucose
III) Promotor site of transcription unit acts as a repressor
EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Name the inducer which regulates the switching on and off of the lac operon.
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
In the presence of glucose and lactose, Escherichia coli utilizes glucose. However, lactose also enters the cells because?
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Which of the following is required as an inducer for the expression of lac operon?
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
When does the lac-operon in E. coli become "switched on"?
HARD
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
In an E. coli strain, i gene gets mutated, and its product cannot bind the inducer molecule. If the growth medium is provided with lactose, what will be the outcome?
EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression

Fill in the blank with the most appropriate option given below.

We should give everyone training in citizenship, but we have______this aspect till now.

MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Match the following genes of the Lac operon with their respective products:
  Column-I     Column-II
a  i gene  i ß-galactosidase
b z gene ii Permease
c a gene iii Repressor
d  y gene iv  Transacetylase

Select the correct option.
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
In Lac operon, lactose acts as an inducer molecule. Evaluate the statement and explain it.
EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
The schematic below describes the states of the lac operon in the absence of lactose. Which ONE of the following happens when lactose is present in the cell?
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MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Describe the structure and function of Lac operon.
HARD
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Discuss lac operon model with the help of a diagram.
EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Which of the following enzymes is not produced by E.coli during lactose catabolism?
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression

In biological systems, proteins (repressors and activators) control gene expression. Repressors bind to promoters and inhibit gene expression. Some promoters require activators for gene expression. These constitute a genetic circuit and are analogous to logic gates in digital electronics. A schematic diagram of a genetic circuit in a cell is shown below. Binding of IPTG to LacI activates transcription from Plac. Binding of arabinose (Ara) to AraC activates transcription from Para.

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 The correct statement(s) regarding the given genetic circuit is/are

MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Match List I with List II: 

List I

List II
A. Gene 'a'  I. Beta-galactosidase  
B. Gene 'y' II. Transacetylase
C. Gene 'i' III. Permease
D. Gene 'z' IV. Repressor protein

Choose the correct answer from the options given below: 

EASY
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
When Escherichia coli cells are cultured in a medium where Lactose is absent, the 'i' gene of Lac Operon continues to produce repressor mRNA, because it is
HARD
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Gene regulation governing lactose operon of E. coli that involves the lac I gene product is:
MEDIUM
Biology>Genetics and Evolution>Molecular Basis of Inheritance>Regulation of Gene Expression
Select the correct match: