In a form of stress response, bacteria synthesize a group of proteins called stress proteins (or heat shock proteins) such as DnaK,DnaJ, GroEL, GroES, and GrpE. DnaK is an ATP […]
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CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
What Happens When the Trp Repressor Cannot Bind Tryptophan? Insights into trp Operon Regulation
29. A mutant Trp repressor (TrpRm) that cannot bind tryptophan is isolated. In this mutant A. Trp operon is constitutively expressed. B. Trp operon is super-repressed. C. Trp repressor does […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
The Role of Protein Modifications: Acetylation, Hydroxylation, and Glycosylation in Degradation, Folding, and Protein-Protein Interactions
In bacteria, N-formyl methionine is the first amino acid to be incorporated into a polypeptide chain. Accordingly, one would think that all bacterial proteins have a formyl group at theiramino […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
How Tryptophan Binding to the trp Repressor Leads to Repression in the trp Operon
In Trp operon, binding of tryptophan to trp repressor lead to (1) Repression (2) Induction (3) Anti termination (4) Attenuation Introduction The trp operon in Escherichia coli is a classic model […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
Tryptophan as the Negative Regulator of the trp Operon in E. coli
Which of the following is negative regulator of trp operon (1) Lactose (2) Allolactose (3) C-AMP (4) Tryptophan The trp operon in Escherichia coli is a classic example of negative gene […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
The Role of Protein Modifications: Acetylation, Hydroxylation, and Glycosylation in Degradation, Folding, and Protein-Protein Interactions
The following statements were made regarding the role of protein modifications A. Attachment of acetyl groups to the amino termini of proteins makes it more resistant to degradation. B. Attachment […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
The Role of Excess Tryptophan as a Co-repressor in trp Operon Regulation
26. In trp operon regulation excess tryptophan act as (1) Inducer (2) Activator (3) Repressor (4) Co-repressor Introduction: The trp Operon and Its Regulatory Logic The trp operon in Escherichia […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
Prokaryotic Protein Initiation: The Role of Formyl Methionine, Deformylase, and Aminopeptidase in Translation and N-Terminal Processing
In prokaryotes, the initiator t-RNA is first charged with a methionine, followed by the addition of a formyl groupto the methionine by the enzyme Met-tRNAtransformylase. Given below are several statements […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
LacI vs. TrpR: How Repressors and Their Ligands Control Gene Expression in E. coli
25. The Lac I and TrpR repressors bind With their ligands allolactose and tryptophan respectively, resulting in alteration of their DNA binding properties. The following statements are made about the […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
Mutations Leading to Constitutive Expression of the lac Operon in E. coli: A Genetic Analysis
24. E. coli mutants isolated from a genetic screen showed following classes of mutations A. Point mutations in lacI B. Deletions immediately downstream of the transcription start site of the […]
