Class 11 Biology Formulas and Key Facts - Complete Revision Sheet
Class 11 Biology key facts, numerical values, classification hierarchies, and important data points for all chapters. Quick revision sheet for CBSE and NEET.
In short: Biology does not have formulas like Physics or Maths, but it has hundreds of key facts, numerical values, classification hierarchies, and process steps that you must know. This chapter-wise revision sheet covers every important data point from Class 11 Biology - cell dimensions, taxonomic categories, physiological values, and more. Perfect for last-minute revision before CBSE exams or NEET.
How to Use This Revision Sheet
In Biology, "formulas" are really key facts - specific numbers, sequences, classifications, and relationships that examiners test directly. This sheet organises them chapter-wise so you can scan quickly before an exam or use them for weekly revision.
Each table lists the key facts you are most likely to be tested on. Memorise the bold entries first - they appear most frequently in board exams and NEET.
17 (C, H, O, N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, B, Mo, Cl, Ni)
Macronutrients
C, H, O, N, P, K, Ca, Mg, S (>0.1% dry weight)
Micronutrients
Fe, Mn, Cu, Zn, B, Mo, Cl, Ni (<0.01% dry weight)
Nitrogen fixation (biological)
Nitrogenase enzyme, requires anaerobic conditions
Photosynthesis equation
6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O
Photosynthesis - light reaction
Occurs in thylakoid membranes
Photosynthesis - dark reaction
Occurs in stroma (Calvin cycle)
C3 plants
First product = 3-PGA (3 carbon), e.g., rice, wheat
C4 plants
First product = OAA (4 carbon), e.g., sugarcane, maize
Respiration equation
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy (ATP)
ATP from 1 glucose (aerobic)
36-38 ATP (theoretical maximum)
Glycolysis
Occurs in cytoplasm, net gain = 2 ATP, 2 NADH
Krebs cycle
Occurs in mitochondrial matrix
ETC
Occurs in inner mitochondrial membrane
RQ (respiratory quotient)
RQ = CO2 produced / O2 consumed
RQ for carbohydrates
1.0
RQ for fats
<1 (~0.7)
RQ for proteins
~0.8
Chapters 16-22 - Animal Physiology
Topic
Key Fact
Blood pH
7.35-7.45
Blood volume (adult)
~5 litres
RBC count (male)
5-5.5 million/mm^3
RBC count (female)
4.5-5 million/mm^3
WBC count
6,000-8,000/mm^3
Platelet count
1.5-3.5 lakh/mm^3
RBC lifespan
~120 days
Haemoglobin (male)
14-16 g/dL
Haemoglobin (female)
12-14 g/dL
Heart rate (resting)
72 beats/minute
Cardiac output
5 litres/minute
Stroke volume
~70 mL
Blood pressure (normal)
120/80 mmHg
Breathing rate
12-16 breaths/minute
Tidal volume
~500 mL
Vital capacity
~3.5-4.5 litres
Residual volume
~1.2 litres
GFR (glomerular filtration rate)
125 mL/min (~180 L/day)
Urine output
1-1.5 L/day
Total bones in adult
206
Total muscles
~639
Cranial nerves
12 pairs
Spinal nerves
31 pairs
Normal body temperature
37 degrees C (98.6 degrees F)
How to Memorise Biology Key Facts
1. Use mnemonics. For taxonomy hierarchy: "King Philip Came Over For Good Spaghetti" (Kingdom, Phylum, Class, Order, Family, Genus, Species). Create your own mnemonics for other sequences.
2. Draw and label. Biology is a visual subject. Drawing cell diagrams, flower structures, and organ systems activates spatial memory. Label everything from memory, then check.
3. Make comparison tables. Mitosis vs meiosis, C3 vs C4 plants, arteries vs veins. Comparison forces your brain to identify differences, which makes both sides stick.
4. Recite numerical values aloud. Blood pH 7.35-7.45, RBC count 5 million, heart rate 72 - say them out loud 5 times. Auditory repetition is surprisingly effective for numbers.
5. Test yourself with Padhaao. Ask the AI tutor to quiz you on any chapter. It will ask specific factual questions and correct you instantly if your answer is off.
Common Mistakes Students Make
Confusing 70S and 80S ribosomes. Prokaryotes have 70S (50S + 30S), eukaryotes have 80S (60S + 40S). Note that 50 + 30 does not equal 70 because S is a sedimentation coefficient, not simple addition.
Mixing up xylem and phloem direction. Xylem transports water upward (roots to leaves). Phloem transports food downward (and in both directions - source to sink).
Forgetting the difference between C3 and C4. C3 first product is 3-PGA (3 carbons). C4 first product is OAA (4 carbons). C4 plants have Kranz anatomy.
ATP count confusion. The theoretical maximum is 38 ATP per glucose, but the actual yield is 36 due to transport costs. Many textbooks use 36. Check which number your board expects.
Mixing up mitosis and meiosis outcomes. Mitosis: 2 diploid cells (identical). Meiosis: 4 haploid cells (genetically different). Write this on a flashcard and review it until it is automatic.
Exam-Day Quick Revision Strategy
Minutes 1-10: Scan the numerical values table (blood pH, RBC count, heart rate, GFR, ATP yield). These are the most commonly tested facts in objective questions.
Minutes 11-20: Review the classification tables - five kingdoms, plant groups, animal phyla. Focus on the key distinguishing feature of each group.
Minutes 21-30: Glance through cell biology facts (organelle sizes, ribosome types) and biomolecule bonds (glycosidic, peptide, phosphodiester).
Minutes 31-35: Quick review of plant physiology equations (water potential, photosynthesis, respiration). Verify you remember RQ values.
FAQ
Does Biology have real formulas like Physics?
Not in the traditional sense. Biology has numerical relationships (RQ = CO2/O2), physiological constants (blood pH = 7.35-7.45), and process equations (photosynthesis, respiration). These serve the same purpose as formulas - they are testable facts you need to know precisely.
Which chapter has the most key facts to memorise?
Animal Physiology chapters (Body Fluids, Excretion, Neural Control) have the most numerical values. Plant Kingdom and Animal Kingdom have the most classification details. Both are heavy on factual recall.
How do I remember all the animal phyla?
Use a mnemonic: "Poor Creatures Can't Pass A Nasty Allergy Medicine, Even Hair" - Porifera, Cnidaria, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata. Create one that makes sense to you.
Is this enough for NEET preparation?
This covers NCERT-level facts, which form the foundation of NEET Biology. NEET questions are primarily NCERT-based, so knowing these facts thoroughly will help you answer most questions. For assertion-reason and application-based questions, you also need conceptual understanding.
Should I memorise exact numbers or ranges?
Memorise the standard values (e.g., blood pH 7.35-7.45, RBC count 5 million/mm^3). In MCQs, the correct option usually matches these standard values. In descriptive answers, mention the range to show thoroughness.
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