Molecular Biotechnology & Analytical Techniques

Molecular Biotechnology & Analytical Techniques

Given below are two statements : Statement I : The restriction enzymes are natural products of Bacteria and they cut the

Restriction enzymes are bacterial endonucleases providing defense against phage, recognizing specific double-stranded palindromic sequences and cleaving both strands. They do not cut single-stranded DNA exclusively; most require double-stranded substrates with defined recognition sites.

Ref: Watson et al., Molecular Biology of the Gene, 7th Edition, Chapter 5 discusses restriction enzymes as bacterial products cutting double-stranded DNA at defined sequences providing host defense, published by Pearson Education.

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Molecular Biotechnology & Analytical Techniques

Nobel Prizes in Immunologic Research Match List I with List II. List I List II (A) Jules Bordet (1919) (I) Development o

Jules Bordet received Nobel 1919 for complement-mediated bacteriolysis discovery. Rosalyn Yalow won 1977 for radioimmunoassay development. Charles Richet was awarded 1913 for anaphylaxis characterization. Niels Jerne obtained 1984 prize for immune regulatory theories including network hypothesis.

Ref: Goldberg et al., Kuby Immunology, 8th Edition, Chapter 1 historical overview details Nobel laureates Bordet for complement, Richet for anaphylaxis, Yalow for radioimmunoassay, and Jerne for immune regulatory theories, published by W.H. Freeman.

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Molecular Biotechnology & Analytical Techniques

Recombinant DNA technology has made it possible to start with a particular gene, make mutations in it, and then create m

Reverse genetics starts from a known gene sequence, introduces targeted mutations in vitro, then generates mutant organisms to infer gene function from phenotype. This contrasts forward genetics where phenotype screening precedes gene identification.

Ref: Watson et al., Molecular Biology of the Gene, 7th Edition, Chapter 20 defines reverse genetics as mutating a cloned gene and creating mutant cells or organisms to study function, published by Pearson Education.

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Molecular Biotechnology & Analytical Techniques

All the following statements are true regarding RFLP and RAPD except :

RFLP requires restriction digestion and is more reliable and reproducible than RAPD. RAPD uses arbitrary short random primers to amplify random genomic regions without needing species-specific primers and without radioactive probes, serving as quick guide method.

Ref: Brown, Genomes 4, 4th Edition, Chapter 5 explains RFLP as reliable Southern blot based method and RAPD using arbitrary random primers without species-specific primers or radioactive probes, published by Garland Science.

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Molecular Biotechnology & Analytical Techniques

Which among the following statements are correct about very long DNA fragments (>100 kb) from eukaryotic genomes? (A) Th

Fragments exceeding 100 kb cannot be packaged efficiently in lambda phage vectors limited to about 45 kb. Yeast artificial chromosomes accommodate megabase inserts with centromere and telomeres. Such large fragments are resolved by pulsed field gel electrophoresis which alternates electric field direction.

Ref: Watson et al., Molecular Biology of the Gene, 7th Edition, Chapter 7 discusses cloning large DNA fragments using YAC vectors and separation of very large fragments by pulsed field gel electrophoresis, published by Pearson Education.

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Molecular Biotechnology & Analytical Techniques

You performed an experiment to create a gene knock out mice to study the function of gene X. During this experiment you

Positive-negative selection uses neo to select transfected ES cells conferring neomycin resistance. Thymidine kinase outside homology arms is lost during homologous recombination but retained in random integration, making non-homologous recombinants ganciclovir-sensitive for negative selection.

Ref: Watson et al., Molecular Biology of the Gene, 7th Edition, Chapter 20 details gene knockout strategy using neo positive selection and tk negative selection to enrich homologous recombinants in ES cells, published by Pearson Education.

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Molecular Biotechnology & Analytical Techniques

Given below are two statements : Statement I : Dynamic light scattering principle can be used to determine the approxima

Dynamic light scattering analyzes fluctuations in scattered light from Brownian motion to calculate hydrodynamic radius and approximate size of proteins in solution. Circular dichroism spectroscopy measures differential absorption of left and right circularly polarized light to assess secondary structure, not direct mapping of protein-ligand interactions.

Ref: Wilson and Walker, Principles and Techniques of Biochemistry and Molecular Biology, 8th Edition, Chapter 13 describes dynamic light scattering for particle size determination and circular dichroism for secondary structure analysis, published by Cambridge University Press.

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Molecular Biotechnology & Analytical Techniques

Which among the following techniques can NOT be used to determine 3D structure of biomolecules?

Cryo-EM, X-ray crystallography and NMR spectroscopy are established methods for determining 3D structures of biomolecules at varying resolutions. SDS-PAGE denatures proteins and separates by molecular weight only, providing size estimation without any three-dimensional structural information.

Ref: Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 8 covers structural biology techniques X-ray crystallography, cryo-EM, NMR as structure determination tools versus SDS-PAGE as analytical electrophoresis method, published by Garland Science.

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Molecular Biotechnology & Analytical Techniques

Which among the following chromatographic methods can be used to separate samples from each other on the basis of size?

Gel filtration, also called size exclusion chromatography, separates molecules based on hydrodynamic volume. Porous beads exclude large molecules which elute early through void volume, while small molecules enter pores and elute later, unlike affinity or ion exchange.

Ref: Wilson and Walker, Principles and Techniques of Biochemistry and Molecular Biology, 8th Edition, Chapter 9 explains gel filtration chromatography principle for size-based separation using porous matrix, published by Cambridge University Press.

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Molecular Biotechnology & Analytical Techniques

Ramachandran plot is widely used to :

Ramachandran plot maps phi and psi backbone dihedral angles to evaluate sterically allowed conformations. Clustered points in favored regions indicate high-quality protein model, while outliers suggest errors needing refinement, thus serving validation tool, not sequencing.

Ref: Lehninger Principles of Biochemistry by Nelson and Cox, 8th Edition, Chapter 4 presents Ramachandran plot for phi-psi analysis and validation of protein three-dimensional structures, published by W.H. Freeman and Company.

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Molecular Biotechnology & Analytical Techniques

Determination of 3D structure of membrane proteins often appears difficult as compared to the cytoplasmic proteins becau

Membrane proteins require detergents for extraction from lipid bilayer, increasing aggregation propensity and heterogeneity. Producing homogeneous, stable, high-concentration samples for crystallization or cryo-EM is technically demanding, not because they lack defined primary or tertiary folds.

Ref: Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 10 discusses membrane protein biochemistry, detergent solubilization challenges and difficulties obtaining homogeneous preparations for structural studies, published by Garland Science.

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Molecular Biotechnology & Analytical Techniques

Match List I with List II. List I List II (A) Tertiary structure (I) Amino acid sequence (B) Primary structure (II) α -

Primary structure is amino acid sequence linked by peptide bonds. Secondary structure refers to local helices and sheets stabilized by hydrogen bonds. Tertiary structure is overall 3D arrangement of secondary elements. Quaternary structure describes spatial assembly of multiple tertiary subunits.

Ref: Lehninger Principles of Biochemistry by Nelson and Cox, 8th Edition, Chapter 4 explains protein structure hierarchy including primary sequence, secondary alpha helices and beta sheets, tertiary arrangement and quaternary assembly, published by W.H. Freeman.

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