Q.67 Which of the following are types of electrophoresis?

A. Competitive
B. Pulsed-field gel
C. Indirect
D. 2-Dimensional

Choose the correct answer from the options given below:

1. A, B, C, D
2. B, D only
3. A, C, D only
4. B, C, D only

   The correct answer is B, D only.

   Pulsed-field gel electrophoresis and 2-dimensional electrophoresis are established types of electrophoresis techniques used in molecular biology labs, while competitive and indirect are not standard classifications.

   Statement Evaluation

   A. Competitive
   False. “Competitive” refers to assay formats (e.g., competitive ELISA), not a type of electrophoresis. No standard electrophoresis method uses this term.

   B. Pulsed-field gel
   True. Pulsed-field gel electrophoresis (PFGE) separates large DNA molecules (>50 kb) by alternating electric field directions, crucial for genome mapping and microbial typing.

   C. Indirect
   False. “Indirect” describes detection methods (e.g., indirect immunofluorescence), not electrophoresis types. It’s not listed among core techniques like gel or capillary.

   D. 2-Dimensional
   True. 2D electrophoresis combines isoelectric focusing (first dimension, by charge) and SDS-PAGE (second dimension, by size), ideal for complex protein mixtures in proteomics.

   Option Breakdown

   Option	Includes	Correct?	Reason
   A, B, C, D	All	No	A & C invalid
   B, D only	B & D	Yes	Standard gel variants
   A, C, D only	A, C, D	No	A & C wrong
   B, C, D only	B, C, D	No	C invalid

   ---

   Types of electrophoresis like pulsed-field gel and 2-dimensional variants are essential molecular biology tools for separating DNA and proteins by size/charge, powering genomics and proteomics research.

   Pulsed-Field Gel Electrophoresis (PFGE)

   PFGE overcomes standard gel limits by pulsing electric fields in different directions, allowing megabase DNA separation (e.g., chromosomes). Developed in 1984, it’s gold-standard for outbreak tracing (PulseNet) and genome mapping.

   2-Dimensional Electrophoresis (2D-PAGE)

   2D electrophoresis resolves thousands of proteins: first dimension (IEF) separates by pI, second (SDS-PAGE) by molecular weight. Key in proteomics for spotting disease biomarkers via spot patterns.

   Why Not Competitive or Indirect?

   These terms belong to immunoassays, not electrophoresis classification. Exams test core types: agarose/PAGE, capillary, PFGE, 2D—focus on gel-based variants for biotech questions.

   Exam Applications

   • NEET/GATE Life Sciences: Recognize PFGE for large DNA; 2D for complex proteomes.

   • Techniques Table:

   Type	Target	Principle
   PFGE	Large DNA	Pulsed fields
   2D Electrophoresis	Proteins	IEF + SDS-PAGE
   Agarose	Small DNA/RNA	Size sieving