Class 12 Biology rewards students who understand concepts, draw accurate diagrams, and write answers with precise biological terms.
Unit-wise Marks Distribution
| Unit | Chapters | Marks |
|---|---|---|
| Reproduction | 1-4 | 16 |
| Genetics and Evolution | 5-7 | 20 |
| Biology in Human Welfare | 8-10 | 12 |
| Biotechnology | 11-12 | 12 |
| Ecology | 13-16 | 10 |
Genetics and Evolution (20 marks — highest priority)
- Draw the DNA double helix and label every component
- Learn all deviations from Mendelism: incomplete dominance, codominance, epistasis
- Central dogma: DNA to RNA to Protein — draw each step
- Hardy-Weinberg: p2 + 2pq + q2 = 1 with examples
Reproduction (16 marks)
- Draw male and female reproductive system — labelled
- Menstrual cycle: FSH/LH hormone levels at each phase
- Embryogenesis: morula, blastula, gastrula sequence
- Double fertilisation in plants
Biotechnology (12 marks)
- PCR steps: denaturation, annealing, extension
- Gel electrophoresis: principle and purpose
- Recombinant DNA technology: restriction enzymes, vectors, host cells
- Bt toxin, insulin production — applications
Tip
Biology diagrams are worth 30-40% of your marks. Practise drawing 2 diagrams daily from memory. This single habit can add 10-15 marks to your score.
Common Mistakes
- Writing 'DNA copies itself' instead of 'semi-conservative replication'
- Unlabelled or incomplete diagrams
- Skipping Ecology — 10 easy marks