Quick Revision Sheet: Biology for RRB CBT
⚡ Last-day crammer – skim, don’t read!
1. Cell & Cell Organelles – “PMR-CLGN-MVP”
| Organelle | Key Job | Memory Hook |
|---|
| Plasma-membrane | Gatekeeper | “P” for Police |
| Mitochondria | ATP (energy) | “M” for Money |
| Ribosome | Protein factory | “R” for Readymade |
| Chloroplast | Photosynthesis | Only in plants |
| Lysosome | Suicide bag | “L” for Lethal |
| Golgi | Packing & postage | “G” for Gift-wrap |
| Nucleus | Brain (DNA) | “N” for Netaji |
🔖 Rule: Prokaryotes lack membrane-bound organelles; Eukaryotes have them.
6CO₂ + 6H₂O ―Sunlight+Chlorophyll→ C₆H₁₂O₆ + 6O₂
Shortcut: “6-6-1-6” (CO₂-H₂O-Glucose-O₂)
3. Human Body Systems – “CARES-DREN”
| System | Chief Point | Mnemonic |
|---|
| Circulatory | Heart 4-chambers | “C” for Cycle pump |
| Respiratory | Alveoli = gas swap | “R” for Reverse osmosis |
| Excretory | Nephron unit | “E” for Exit gate |
| Skeletal | 206 bones | Adult = 206, New-born = 270 |
| Digestive | Longest = Small intestine (6 m) | “D” for Dinner tube |
4. Blood – “BBC-CLP”
| Component | Normal Count | Exam Trap |
|---|
| RBC | 5 million/µL | No nucleus |
| WBC | 5 000–11 000/µL | Fight infection |
| Platelets | 1.5–4 lakh/µL | Clotting |
| Haemoglobin | Men 14–16 g/dL, Women 12–14 g/dL | O₂ carrier |
Universal donor = O⁻ (O-negative)
Universal recipient = AB⁺
5. Disease & Carrier – “2-TB, 2-V, 2-P”
| Disease | Cause | Vector / Carrier |
|---|
| TB | Bacteria (Myco.) | Air droplets |
| Typhoid | Bacteria (Sal.) | Contaminated water |
| Malaria | Protozoa (Plas.) | Female Anopheles |
| Kala-azar | Protozoa (Leish.) | Sand-fly |
| AIDS | Virus (HIV) | Blood / Body fluid |
| Hep-B | Virus | Blood / Syringe |
6. Genetics – Mendel’s 3:1
- Dominant > Recessive (Tall = Dominant)
- Genotype = Letter code (TT, Tt, tt)
- Phenotype = Look (Tall, Dwarf)
7. Plant Kingdom – “BAG-F”
| Group | Vascular? | Seeds? | Example |
|---|
| Bryophyta | ❌ | ❌ | Moss |
| Angiosperm | ✅ | ✅ Covered | Mango |
| Gymnosperm | ✅ | ✅ Naked | Pine |
| Fungi | ❌ (separate) | ❌ | Mushroom |
8. Vitamins & Night-Deficiency – “ABCDE-K”
| Vitamin | Deficiency Disease | Quick Note |
|---|
| A | Night-blindness | Carrot (β-carotene) |
| B₁ | Beri-beri | Rice polish |
| C | Scurvy | Citrus |
| D | Rickets | Sun-light |
| K | Clotting failure | Green leafy |
9. Common Exam Q&A – Micro-Capsules
1. Largest human cell?
Ovum (egg cell)2. Power-house of cell?
Mitochondria3. Normal blood pressure?
120/80 mmHg4. CO₂ transport mainly as?
Bicarbonate ion (HCO₃⁻)5. Father of Genetics?
Gregor Mendel6. Total cranial nerves?
12 pairs7. pH of human blood?
7.4 (slightly alkaline)8. Yellow fever vector?
Aedes aegypti mosquito
10. 60-Second Table – Must-Know Numbers
| Fact | Number |
|---|
| Chromosomes in man | 46 (23 pairs) |
| RBC life span | 120 days |
| Normal heartbeat | 72/min |
| IQ formula | (Mental age ÷ Real age) × 100 |
| Vaccine for TB | BCG |
| Vaccine for Polio | OPV (oral) |
| Vaccine for Tetanus | TT |
| Insulin source | Pancreas (β-cells) |
🎯 Last-night chant: “PMR-CLGN-MVP, 6-6-1-6, O⁻ AB⁺, BBC-CLP, BAG-F, A-B-C-D-K”
All the best—attempt, don’t leave!
BETA
