The PDF also contains a 20-page "Rapid Fire" section—400 one-liners for last-night revision. 7. Comparison: Khan Sir Biology PDF vs. Other Popular Biology Notes | Feature | Khan Sir PDF | Ravi Sir Biology | NCERT Biology (Class 11-12) | Lucent GK Biology | | --- | --- | --- | --- | --- | | Language | Hinglish | Hindi | English | English/Hindi | | Diagrams | Hand-drawn & labeled | Basic | High-quality color | Black & white | | Exam focus | SSC, Railway, UPSC | State exams, SSC | CBSE, NEET | All competitive | | Memory tricks | Extensive mnemonics | Some | None | Few | | Price (approx) | Free–300 INR | 200–500 INR | 200 INR (two books) | 150 INR |

Let’s dive deep. The Khan Sir Biology PDF is a digital compilation of handwritten classroom notes, diagrams, and memory tricks derived directly from Khan Sir’s live coaching sessions. Unlike traditional textbooks (NCERT or Lakhmir Singh), this PDF is designed for last-minute revision and concept clarity through a lens of competitive examination patterns.

In several videos, he has expressed that education should be free, but pirated PDFs hurt his ability to maintain quality and pay staff. He encourages students to use his official YouTube channel (free video lectures) and buy the PDF only if affordable.

| | Key Subtopics | # of PYQs Covered | | --- | --- | --- | | The Living World | Taxonomy, 5-kingdom classification | 45 | | Cell Structure | Mitochondria, Ribosomes, Nucleus | 78 | | Plant Physiology | Photosynthesis, Transpiration, Gibberellins | 52 | | Human Digestion | Enzymes, Stomach, Liver, Pancreas | 93 | | Respiratory System | Lungs, Alveoli, Hemoglobin | 67 | | Circulatory System | Blood groups (ABO, Rh), ECG, Heart chambers | 112 | | Excretory System | Nephron, Urea cycle, Dialysis | 58 | | Nervous System | Neuron, Brain parts, Reflex arc | 71 | | Endocrine System | All glands + hormones + disorders | 104 | | Reproduction | Menstrual cycle, IVF, Contraception | 86 | | Genetics | DNA replication, Punnett square | 65 | | Diseases | Malaria, Typhoid, AIDS, COVID-19 | 93 | | Environment | Ozone depletion, Greenhouse effect | 47 |