Choose the correct answer from the options given below:

1. (A) – (II), (B) – (I), (C) – (IV), (D) – (III)
2. (A) – (II), (B) – (IV), (C) – (I), (D) – (III)
3. (A) – (I), (B) – (II), (C) – (IV), (D) – (III)

4. • Option 1 (Correct): Perfectly matches standard definitions above.​

   • Option 2: Swaps B/C (DNA/RNA reversed)—common error.​

   • Option 3: Scrambles A/B (protein/DNA swapped).​

   • Option 4: Confuses interactions with blotting entirely.​(A) – (III), (B) – (IV), (C) – (I), (D) – (II)

     Correct Answer: 1. (A) – (II), (B) – (I), (C) – (IV), (D) – (III)

     These blotting techniques and yeast two-hybrid system are fundamental molecular biology tools for nucleic acid and protein analysis, commonly tested in GATE Life Sciences. The matching follows standard nomenclature: “Western” for proteins, “Southern” for DNA, “Northern” for RNA, with yeast two-hybrid detecting interactions.

     Technique Matching

     A. Western Blotting → II. Protein identification

     Western blotting separates proteins by SDS-PAGE, transfers them to a membrane, and detects specific targets using antibodies. It’s the gold standard for confirming protein expression, size, and modifications in complex samples.

     B. Southern Blotting → I. DNA identification

     Southern blotting hybridizes DNA fragments (post-restriction digest/electrophoresis) with labeled probes on a membrane. It identifies specific DNA sequences, used historically for RFLP genotyping and gene mapping.​

     C. Northern Blotting → IV. RNA identification

     Northern blotting analyzes RNA size and abundance by electrophoresis, transfer, and hybridization. It distinguishes mRNA isoforms and expression levels, though largely replaced by RT-PCR.​

     D. Yeast two-hybrid system → III. Protein-protein interaction

     This genetic assay uses hybrid proteins: one fused to DNA-binding domain (bait), another to activation domain (prey). Interaction reconstitutes transcription, identifying binding partners via reporter gene activation.​

     Option Analysis

   Match list western blotting southern blotting questions test core molecular biology techniques crucial for GATE Life Sciences. This matching MCQ pairs techniques with functions: Western (proteins), Southern (DNA), Northern (RNA), and Yeast two-hybrid (interactions). Master the distinctions for exam success.

   Technique Breakdown

   Blot Family (Edwin Southern inspired naming):

   • Southern Blot: DNA restriction fragments → gel → membrane → probe hybridization = DNA ID.​

   • Northern Blot: Total RNA/mRNA → denaturing gel → membrane → RNA probe = RNA expression.

   • Western Blot: Proteins → SDS-PAGE → nitrocellulose/PVDF → antibody detection = Protein ID.

   Yeast Two-Hybrid: Split GAL4 system—bait-prey interaction drives HIS3/LacZ reporters.​

   Correct Matching Table

   Technique	Function	Principle ​
   A. Western	II. Protein ID	SDS-PAGE + antibodies
   B. Southern	I. DNA ID	Restriction + DNA probe
   C. Northern	IV. RNA ID	Denaturing gel + RNA probe
   D. Yeast 2-Hybrid	III. Protein interaction	Transcriptional activation

   Mnemonic: “WSPN” → Western(Protein), Southern(DNA), Northern(RNA)

   GATE PYQ Pattern

   Appears in Biomolecules/Techniques (20% weightage). Variants test FAR-WESTERN (protein-DNA) or modifications. Focus: probe/antibody specificity.​

   Pro Tip: Remember directional naming—Southern (creator) → West (proteins), North (RNA). Yeast 2-hybrid is interaction-only, not blotting.