Cell Biology – NEET‑VET Study Notes
Target audience – Students preparing for the NEET‑VET exam.
Goal – Equip you with a concise yet comprehensive, exam‑oriented understanding of cell biology, complete with derivations, key formulae, and pitfalls.
1. Overview
| Topic | Key Points | Exam Relevance |
|---|---|---|
| Cellular Organization | Prokaryotic vs. eukaryotic; plant vs. animal | Basic classification questions |
| Cell Structure | Organelles, membrane composition, cytoskeleton | Spot‑on diagrams, functional questions |
| Cell Cycle & Division | G1, S, G2, M; mitosis vs. meiosis | Pathology & genetics questions |
| Molecular Biology | DNA replication, transcription, translation | Molecular pathway questions |
| Transport & Signalling | Osmosis, diffusion, active transport, membrane potential, signalling pathways | Pharmacology & physiology questions |
| Special Topics | Stem cells, apoptosis, cytoskeletal dynamics | Advanced pathology |
Tip – Draw the cell diagram once and label all organelles. Re‑use this figure for subsequent questions.
2. Cellular Organization
| Prokaryotes | Eukaryotes |
|---|---|
| No nucleus, no membrane‑bound organelles | Nucleus, endomembrane system, mitochondria, chloroplasts |
| Small genome (≤ 6 Mb) | Large genome (usually > 100 Mb) |
| Cell wall – peptidoglycan (Gram‑+) or lipopolysaccharide (Gram‑−) | Cell wall – cellulose (plants) or none (animals) |
| Binary fission | Mitosis & meiosis |
Tricky Point – Bacteria can have plasmids that encode antibiotic resistance; remember the distinction from chromosomal DNA.
3. Cell Structure & Function
3.1 Plasma Membrane
- Structure: Phospholipid bilayer + cholesterol + sphingolipids + embedded proteins.
- Key Functions: Selective permeability, signal transduction, cell‑cell adhesion.
3.1.1 Lipid‑Protein Interactions
| Protein Type | Location | Function |
|---|---|---|
| Integral | Span bilayer | Channels, receptors, pumps |
| Peripheral | Outside or cytoplasmic side | Enzymes, cytoskeletal anchors |
| Lipid‑anchored | Covalently attached | Signal transduction (e.g., G‑protein coupled receptors) |
3.2 Organelles
| Organelle | Main Function | Key Notes |
|---|---|---|
| Nucleus | DNA storage, transcription | Envelope with nuclear pores; nucleolus for ribosomal RNA |
| Mitochondria | Oxidative phosphorylation | Double membrane; own DNA (12–16 kb in vertebrates) |
| Chloroplast | Photosynthesis | Thylakoid membrane; own DNA (≈ 200 kb) |
| Ribosomes | Protein synthesis | 80S in cytosol; 70S in mitochondria & chloroplast |
| Endoplasmic Reticulum | Protein (RER) & lipid (SER) synthesis | Rough ER has ribosomes; SER is smooth |
| Golgi Apparatus | Post‑translational modification, sorting | Cis‑ to trans‑Golgi stack |
| Lysosomes | Degradation | Acidic; contains hydrolases |