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 […]
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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 […]
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Understanding Post-Translational Modifications in Mammalian Systems: Palmitoylation, Glycosylation, Phosphorylation, and Peptidylation
Which of the following is NOT a post-translational modification in a mammalian system? (1) palmitoylation (2) glycosylation (3) peptidylation (4) phosphorylation Introduction to Post-Translational Modifications Post-translational modifications (PTMs) are chemical […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
When Is β-Galactosidase Expressed in a trp-lac Operon Fusion? Understanding the Impact of Tryptophan Levels
23. In an experimental approach regulatory sequences of trp operon were fused with structural genes of lac operon. Under what condition there would be expression Of β-galactosidase? (1) Low lactose […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
Understanding Co-Translational Protein Modification: Myristoylation vs. Palmitoylation, Farnesylation, and Cholesterol Addition
Which one of following modification of proteins is co translational? (1) Palmitoylation (2) Myristoylation (3) Famesylation (4) addition of cholesterol Introduction to Protein Modification Proteins undergo a variety of modifications […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
How to Identify Structural, Operator, and Repressor Genes in a Hypothetical Amino Acid Operon
A hypothetical operon involved in the synthesis of an amino acid ‘X’ is ‘ON’ (transcribing) in the presence of low levels of ‘X’ and ‘Off’ (not transcribing) in presence of […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
Understanding mRNA Premature Termination: How Transition Mutations in UAA Stop Codon Can Reverse Immature Termination
In m-RNA immature termination occurs due to stop codon UAA. Which of the following transition mutation will lead to its reversal? (1) Change at first U (2) Change at first […]
CSIR NET Life Science Previous Year Questions and Solution on Molecular Biology
Prokaryotic Translation Termination: Mechanism of Release Factors RF1, RF2, and RF3 in Stop Codon Recognition and Polypeptide Release
During translation in prokaryotes, when ribosomes reach the termination codon, the termination codon is recognized by the class I release factors (RF1 or RF2) leading to the release of the […]
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How Is Protein Synthesis Terminated? Understanding the Role of Stop Codons and Release Factors in Translation
The genetic code has 61 codons for amino acids and termination codons. How protein synthesis is terminated? (1) There are specific tRNAs for stop codons (2) Release factors mediate termination […]
