How NEET Tests 'Cell' - High-Yield Traps
This is one of the highest-yield NEET chapters, and the hard questions are discriminators, counts and exceptions. Master these rank-splitters:
- Ribosome size: 80S = eukaryotic cytoplasm (60S + 40S); 70S = prokaryote AND mitochondria + chloroplasts (50S + 30S). (S does not add simply - a 60S + 40S give an 80S monosome.)
- Membrane-bound vs NOT: NOT membrane-bound → ribosomes, nucleolus, centriole, inclusion bodies, cytoskeleton. Membrane-bound → nucleus, ER, Golgi, lysosome, vacuole, mitochondrion, plastid, peroxisome. Single membrane → ER, Golgi, lysosome, vacuole, peroxisome; double membrane → nucleus, mitochondrion, chloroplast.
- Semi-autonomous organelles = mitochondria + plastids (own circular DNA + 70S ribosomes + self-division).
- 9 + 2 vs 9 + 0: cilia/flagella axoneme = 9+2; basal body & centriole = 9+0.
- Prokaryote vs eukaryote: no nuclear membrane, no membrane-bound organelles, 70S ribosomes, wall of peptidoglycan, DNA naked/circular → prokaryote. Inclusion bodies are not membrane bound; mesosome is a plasma-membrane infold.
- Endomembrane system = ER + Golgi + lysosome + vacuole (mitochondria, chloroplast and peroxisome are excluded).
- RER vs SER: ribosomes + protein synthesis (RER) vs lipid/steroid synthesis, no ribosomes (SER).
- Golgi: cis (forming) face near the ER, trans (maturing) face away; the packaging/secretion organelle.
- Chromosome types by centromere position (metacentric/sub-metacentric/acrocentric/telocentric) and the satellite/SAT-chromosome at the secondary constriction.
- Fluid-mosaic model (Singer & Nicolson): quasi-fluid lipid bilayer with proteins; polar heads out, tails in; active transport needs ATP.
Below are challenging assertion-reason, match-the-column, multi-statement and sequence questions built on exactly these distinctions.