CBSE Class 12 Biology Formulas and Key Equations
CBSE Class 12 Biology formulas and key values: genetics ratios, Hardy-Weinberg, population growth, productivity and species-area equations for 2027.
Biology is concept-heavy, but there are key formulas, ratios, and numerical values you must know for the CBSE Class 12 board exam. Here is a quick reference for the 2027 exam.
For chapter-wise notes, open our CBSE Class 12 Biology formula sheets.
Genetics Formulas and Ratios
- Monohybrid cross ratio — 3:1 (phenotypic), 1:2:1 (genotypic).
- Dihybrid cross ratio — 9:3:3:1 (phenotypic).
- Test cross ratio — 1:1 for heterozygous parent.
- Hardy-Weinberg equation — p² + 2pq + q² = 1.
Ecology Formulas
- Net Primary Productivity — NPP = GPP - Respiration.
- Energy flow — 10% law (Lindeman's efficiency).
- Population growth — dN/dt = rN (exponential) or dN/dt = rN(K-N)/K (logistic).
- Species-area relationship — log S = log C + Z log A.
Key Numerical Values
- Human genome — about 3 × 10⁹ base pairs (NCERT gives 3164.7 million nucleotide bases).
- Number of chromosomes — 46 (23 pairs) in humans.
- Blood groups — A, B, AB, O (ABO system) + Rh factor.
- Normal body temperature — 37°C / 98.6°F.
Practise Biology concepts
Super Tutor has chapter-wise Biology revision notes, flashcards and practice quizzes for CBSE Class 12.
Try it freeBased on the CBSE Class 12 Biology syllabus 2026-27 and NCERT textbook.
Turn this into exam marks
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Start freeFrequently Asked Questions
Does Biology have many formulas?
Biology has fewer formulas than Physics or Chemistry, but key genetic ratios, ecological equations, and physiological values are frequently tested.
How to remember Biology formulas?
Use visual aids — draw Punnett squares for genetics, flowcharts for ecology. Practice numerical problems to reinforce the formulas.