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#diagnostics

7 public questions tagged with this topic.

Which technique is used for the early detection of HIV in suspected patients?

PCR is used to amplify and detect even small amounts of viral DNA, making it suitable for early HIV detection. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Principles of Inheritance, Molecular Basis of Inheritance and Biotechnology, Topic: Genetics, DNA techniques and applications.

Which of the following is correct about molecular diagnostics?

Molecular diagnostics uses techniques like PCR to detect pathogens, genetic mutations, and other molecular markers in biological samples. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which of the following is incorrect regarding molecular diagnostics?

Molecular diagnostics does not rely solely on visual inspection; it uses techniques like PCR and hybridization to detect genetic materials. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function.

Which of the following is incorrect about molecular diagnostics?

Molecular diagnostics does not rely solely on light microscopy; it uses advanced techniques like PCR and hybridization for accurate detection. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Monoclonal antibodies bind:

Monoclonal antibody originates from unique genetic event where one developing B cell successfully completed VDJ recombination on heavy chain locus chromosome 14 mediated by RAG1/2 recognition of recombination signal sequences, non-homologous end joining with TdT adding N nucleotides creating unique complementarity determining region three loop that dominates antigen contact, plus VJ recombination on light chain locus producing paired variable domains. All progeny via mitosis carry identical nucleotide sequence encoding paratope whose three-dimensional shape, electrostatic surface, and hydrophobic pockets complement single epitope topology defined by side chain arrangement and glycan. Binding affinity Kd remains uniform across preparation because combining site does not vary, allowing quantitative analysis via Scatchard plot and predictable off-rate. Even bivalent IgG displays same intrinsic affinity per Fab arm, avidity only increases with multivalent antigen. Such uniformity reduces nonspecific background in immunohistochemistry where inconsistent binding creates noise, enables precise epitope mapping using alanine scanning mutagenesis, and ensures reproducible pharmacokinetics with linear clearance. Uniform binding to single epitope with constant affinity distinguishes monoclonal from heterogeneous polyclonal mixture containing varying avidities and cross-reactivities that compromise quantitation.

Ref: Abbas Cellular Molecular Immunology 10th ed monoclonal single epitope uniform affinity; Roitt Essential Immunology specificity.

What is the use of flow cytometry?

Flow cytometry analyzes physical and chemical properties of individual cells suspended in fluid. Hydrodynamic focusing forces single file passage through laser intercept, measuring forward scatter proportional to size, side scatter indicating granularity, and fluorescence from labeled antibodies or dyes reflecting antigen expression, DNA content or calcium flux. It does not sequence DNA, assess protein tertiary folding or amplify nucleic acids like PCR. Applications include immunophenotyping, cell cycle analysis, apoptosis detection, sorting of specific populations for culture, making it powerful for quantitative cellular property measurement.

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.