⚡ NEET Revision Kit: Rapid Recall (Cell: Structure & Function)
This section is designed for quick revision before tests and NEET. It collects the most frequently repeated facts and patterns from previous years.
🧠 1) "Who Said What?" — Super High-Yield List
These names are repeatedly asked in MCQs and match-the-following.
✅ Scientists & Contributions
- Robert Brown (1831) → Discovered the nucleus.
- Schleiden (1838) → Said plants are made of cells.
- Schwann (1839) → Said animals are made of cells.
- Rudolf Virchow (1855) → Omnis cellula e cellula → new cells arise from pre-existing cells.
- Singer & Nicolson (1972) → Fluid Mosaic Model of plasma membrane.
- George Palade (1953) → First observed ribosomes.
- Camillo Golgi (1898) → Discovered Golgi apparatus.
🔑 Memory Trick (Timeline Feel):
Brown → Schleiden/Schwann → Virchow → Palade → Singer & Nicolson
🧬 2) The "Semi-Autonomous" Twins (Very Common PYQ)
✅ Mitochondria and Chloroplasts are called semi-autonomous because:
- They are double membrane-bound.
- They have circular DNA.
- They have 70S ribosomes.
- They can synthesize some proteins.
- They can divide by fission.
🔑 Key Line:
Own DNA + own ribosomes = semi-autonomous.
🌀 3) The 9+2 vs 9+0 Rule (NEET Favourite)
This is one of the most repeated patterns in PYQs.
✅ 9 + 2 Arrangement
- Found in cilia and flagella (axoneme)
- Role: movement
- Meaning: 9 peripheral doublets + 2 central singlets
✅ 9 + 0 Arrangement
- Found in centrioles / basal bodies
- Role: spindle formation / cell division
- Meaning: 9 peripheral triplets + no central microtubules
🔑 Memory Trick:
9+2 = Move | 9+0 = Divide
🧬 4) Ribosome Math (Easy Marks)
✅ Prokaryotic ribosome
- 70S = 50S + 30S
✅ Eukaryotic cytoplasmic ribosome
- 80S = 60S + 40S
✅ Extra High-Yield Point
- Ribosomes in mitochondria and chloroplasts are also 70S.
🔑 Key Line:
70S inside mitochondria/chloroplast = strong support for endosymbiotic idea.
📦 5) Endomembrane Squad (Coordinated System)
Endomembrane system means organelles that work in a flow-like coordination.
✅ Included:
- ER → Golgi → Lysosome → Vacuole
❌ Not Included:
- Mitochondria, chloroplasts, peroxisomes (independent roles)
🔑 Key Line:
ER makes → Golgi modifies & packs → Lysosome digests → Vacuole stores.
🧷 6) Chromosome Shapes (Based on Centromere Position)
These shapes are asked in MCQs and diagrams.
✅ Metacentric → centromere in middle → V-shape (equal arms)
✅ Sub-metacentric → slightly off-centre → L-shape
✅ Acrocentric → near one end → J-shape
✅ Telocentric → terminal centromere → I-shape
🔑 Memory Trick:
Meta-middle, Sub-slight, Acro-almost end, Telo-terminal.
🧠 Final Rapid Recall (One Screen)
- Brown → nucleus
- Schleiden/Schwann → cell theory
- Virchow → new cells from old cells
- Singer & Nicolson → fluid mosaic
- Palade → ribosomes
- Golgi → packaging organelle
- Semi-autonomous → mitochondria & chloroplast
- 9+2 → movement; 9+0 → division
- 70S/80S subunits → must memorise