PYQ Pattern Analysis for CB-01
Category 1: Ribosome Type and Location (Highest Frequency — 4+ questions/year)
| PYQ Pattern | Typical Stem | Answer | Year Pattern |
|---|---|---|---|
| Mitochondrial ribosomes | "Ribosomes in mitochondrial matrix are of ___ type" | 70S | Very common |
| Organelle ribosome | "Which organelle has 70S ribosomes in eukaryotic cell?" | Mitochondria and Chloroplasts | Common |
| Subunit identification | "30S + 50S = ___ ribosome, found in ___" | 70S, prokaryotes | Common |
| Antibiotic mechanism | "Streptomycin inhibits ___ subunit of ___ ribosome" | 30S, 70S | Occasional |
Strategy: Always remember the "70S rule" — 70S is for prokaryotes AND organelles (mito + chloro). Never 80S for organelles, never 70S for eukaryotic cytoplasm.
Category 2: Organelle Nicknames (Medium Frequency)
| Nickname | Organelle | Supporting Reason |
|---|---|---|
| "Suicide bags" | Lysosomes | Hydrolytic enzymes cause autolysis if ruptured |
| "Powerhouse" | Mitochondria | ATP production via oxidative phosphorylation |
| "Semi-autonomous" | Mitochondria + Chloroplasts | Own DNA + ribosomes + self-replication |
| "Post office" | Golgi apparatus | Receives, sorts, sends proteins to destinations |
Category 3: Prokaryote vs Eukaryote (High Frequency)
NEET favorite question format: "Which of the following is NOT found in prokaryotic cells?"
- Answer typically: nuclear membrane, histones, 80S ribosomes, membrane-bound organelles
Reverse format: "Which is ONLY in prokaryotic cells?"
- Answer typically: peptidoglycan cell wall, mesosomes, plasmids (mostly), 70S ribosomes everywhere
Category 4: Singer and Nicolson / Fluid Mosaic Model
- Year 1972 is directly tested
- "Who proposed Fluid Mosaic Model?" → Singer and Nicolson
- Do not confuse with Davson-Danielli (1935, sandwich model) or Watson-Crick (DNA double helix, 1953)
Category 5: Plant vs Animal Cell Features
NEET pattern: List structures and identify if plant or animal cell
- Cell plate formation → Plant cell (Golgi → cell plate → new cell wall)
- Cleavage furrow → Animal cell (actin-myosin ring)
- Large vacuole + cell wall + plastids → Plant
- Centrioles + lysosomes → Animal
NEET 5-Year Frequency Summary
| Topic | Estimated Questions (2019–2024) |
|---|---|
| Ribosome type/location | 4–6 questions |
| Organelle identification/function | 6–8 questions |
| Prokaryote vs Eukaryote | 3–5 questions |
| Cell Theory scientists | 2–3 questions |
| Plant vs Animal cell | 3–4 questions |
| Fluid Mosaic Model | 1–2 questions |