Q.49 Match List I with List II
LIST I
Technique |
LIST II
Application |
| A. Polymerase chain reaction (PCR) |
I. Specific identification of DNA molecules |
| B. Southern blotting |
II. Specific identification of proteins |
| C. Northern blotting |
III. Cell-free amplification of DNA molecules |
| D. Western blotting |
IV. Specific identification of RNA molecules |
Choose the correct answer from the options given below:
1. A-III, B-II, C-IV, D-I
2. A-III, B-I, C-IV, D-III
3. A-II, B-IV, C-I, D-III
4. A-II, B-III, C-I, D-IV
PCR amplifies DNA, Southern blotting identifies DNA, Northern blotting identifies RNA, and Western blotting identifies proteins.
The correct matching is A-III, B-I, C-IV, D-II (option 1).
Question Breakdown
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A. Polymerase chain reaction (PCR): Cell-free amplification of DNA molecules via thermal cycling
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B. Southern blotting: Specific identification of DNA molecules (restriction digest → gel → probe hybridization)
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C. Northern blotting: Specific identification of RNA molecules (RNA gel → probe)
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D. Western blotting: Specific identification of proteins (SDS-PAGE → antibody detection)
Option Analysis
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1. A-III, B-I, C-IV, D-II: Correct (classic molecular biology matching)
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2. A-III, B-I, C-IV, D-III: Wrong (Western ≠ DNA ID)
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3. A-II, B-IV, C-I, D-III: Wrong (PCR ≠ protein ID)
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4. A-II, B-III, C-I, D-IV: Wrong (multiple mismatches)
Correct Answer
1. A-III, B-I, C-IV, D-II
Molecular Biology Blotting Techniques
Polymerase chain reaction (PCR) enables cell-free amplification of DNA molecules (10^6-10^9 copies in hours). Southern blotting uses radioactive/nucleic acid probes for specific identification of DNA molecules post-restriction digestion. Northern blotting detects specific RNA molecules (gene expression). Western blotting (protein immunoblot) identifies specific proteins via primary/secondary antibodies.
Correct Technique Matching
| Technique |
Application |
| A. PCR |
III. Cell-free amplification of DNA (Taq polymerase) |
| B. Southern |
I. Specific identification of DNA molecules (Southern 1975) |
| C. Northern |
IV. Specific identification of RNA molecules |
| D. Western |
II. Specific identification of proteins (Burnette 1981) |
Blotting Technique Flow
DNA → Restriction → Gel → Blot → Probe = **Southern**
RNA → Denature → Gel → Blot → Probe = **Northern**
Protein → SDS-PAGE → Blot → Antibody = **Western**
Exam Strategy
NEET/GATE mnemonic: “Order: S-N-W (Southern-Northern-Western); PCR = Amplify first”. Option 1 gold standard. Distractors swap protein/RNA detection.
| Molecule |
Technique |
| DNA amplify |
PCR |
| DNA detect |
Southern |
| RNA detect |
Northern |
| Protein detect |
Western |
