Double fertilisation
Syngamy + triple fusion → zygote + endosperm (3n)
One sheet · NCERT · Board revision
Class 12 Biology Formula Sheet
14 formulas from Mathematics and Science, chapter by chapter. Search, filter, copy, or print. This is a revision sheet — not a replacement for the textbook derivation.
Practice questions aligned to NCERT topics used in CBSE classrooms. These are original exam-oriented questions for revision — not official CBSE board papers and not a guarantee of any exam question. Always match the textbook issued by your school and the latest PDFs on ncert.nic.in and cbseacademic.nic.in.
🧬 Class 12 · Biology
Sexual Reproduction in Flowering Plants
🧬 Class 12 · Biology
Human Reproduction
Menstrual cycle
≈ 28 days; ovulation around day 14
🧬 Class 12 · Biology
Principles of Inheritance and Variation
Monohybrid
F2 3 : 1 phenotype
Dihybrid
F2 9 : 3 : 3 : 1
Hardy–Weinberg (also Evolution)
p² + 2pq + q² = 1, p + q = 1
🧬 Class 12 · Biology
Molecular Basis of Inheritance
Chargaff
A = T, G ≡ C (DNA)
Base pairing
A–T two H-bonds; G–C three H-bonds
From chapter list
A=T, G≡C pairing
🧬 Class 12 · Biology
Evolution
Hardy–Weinberg
p² + 2pq + q² = 1
🧬 Class 12 · Biology
Organisms and Populations
Exponential growth
dN/dt = r N
Logistic growth
dN/dt = r N (K − N)/K
🧬 Class 12 · Biology
Ecosystem
NPP
NPP = GPP − R
10% law
≈ 10% energy to next trophic level
🧬 Class 12 · Biology
Biotechnology: Principles and Processes
PCR idea
Denaturation → annealing → extension (repeat)
Also open
FAQs
Are these all official board formulas?
They are the standard NCERT relations used in CBSE Maths and Science papers. Always match the edition issued by your school.
Why are some Biology items short?
Biology is mostly definitions. Only equations and standard ratios (photosynthesis, Hardy–Weinberg, growth models) sit on this sheet.
Will a formula come as-is in the exam?
Often the paper asks you to use a formula, not recite it. Practise a numerical or a derivation after you memorise the line.