Biology Formula Sheet | NEET | Key Terms & Quick Revision

🧬 Biomolecules Key Formulas

Important Formulas

Energy from Glucose

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 36-38 ATP

Aerobic respiration - complete oxidation of glucose

36 ATP in eukaryotes, 38 in prokaryotes

Energy from Fatty Acids

1g fat = 9 kcal

Calorific value of fats

More energy than carbohydrates

Energy from Carbohydrates

1g carbohydrate = 4 kcal

Calorific value of carbohydrates

Same as proteins

Energy from Proteins

1g protein = 4 kcal

Calorific value of proteins

Same as carbohydrates

BMR Formula

BMR = (weight in kg × 24) / 4.18

Basal Metabolic Rate (approx)

Varies with age, gender, activity

pH Scale

pH = -log₁₀[H⁺]

Measure of acidity/alkalinity

Normal blood pH: 7.35-7.45

Key Terms

Monomer

Single unit of a polymer (e.g., amino acid for protein)

Polymer

Chain of monomers (e.g., protein, DNA, starch)

Peptide Bond

Bond between amino acids (-CO-NH-)

Glycosidic Bond

Bond between monosaccharides

Phosphodiester Bond

Bond linking nucleotides in DNA/RNA

Hydrogen Bond

Weak bond between H and O/N/F

🔬 Cell Biology Key Formulas & Terms

Important Formulas

Surface Area to Volume Ratio

SA/V = 3/r (for sphere)

As cell size increases, SA/V decreases

Limits cell size

Osmotic Pressure

π = iCRT

i = van't Hoff factor, C = concentration, T = temperature

R = 0.0821 L·atm/mol·K

Diffusion Rate

Rate ∝ (ΔC × A) / d

ΔC = concentration difference, A = area, d = distance

Fick's Law

Water Potential

Ψ = Ψ_s + Ψ_p

Ψ_s = solute potential, Ψ_p = pressure potential

Water moves from high to low Ψ

Mitotic Index

MI = (Number of dividing cells / Total cells) × 100

Measure of cell division rate

Higher in actively dividing tissues

Key Terms

Prokaryotic Cell

No nucleus, no membrane-bound organelles

Eukaryotic Cell

Has nucleus and membrane-bound organelles

Mitochondria

Powerhouse of the cell, site of ATP synthesis

Chloroplast

Site of photosynthesis in plants

Lysosome

Suicidal bag, contains hydrolytic enzymes

Ribosome

Site of protein synthesis

Mnemonics

🔑 "TAN HAZ" - Cell Organelles & Functions

T = Transport (ER), A = ATP (Mitochondria), N = Nucleus (Genetic material), H = Hydrolytic (Lysosomes), A = Amino acids (Ribosomes), Z = Zymogen (Golgi)

🔑 "MRS GREN" - Life Processes

M = Movement, R = Respiration, S = Sensitivity, G = Growth, R = Reproduction, E = Excretion, N = Nutrition

🧠 Human Physiology Key Formulas & Terms

Important Formulas

Cardiac Output

CO = Heart Rate × Stroke Volume

Amount of blood pumped per minute

Normal: ~5 L/min

Blood Pressure

BP = Cardiac Output × Total Peripheral Resistance

Systolic/Diastolic (e.g., 120/80 mmHg)

Normal: 120/80 mmHg

Respiratory Rate

Normal: 12-20 breaths/min

Average breathing rate in adults

Higher in children

Lung Capacity (VC)

VC = TV + IRV + ERV

Vital Capacity = Tidal + Inspiratory Reserve + Expiratory Reserve

Normal: ~4.8 L

GFR (Glomerular Filtration Rate)

GFR = K_f × Net Filtration Pressure

Rate of filtration in kidneys

Normal: ~125 mL/min

Body Mass Index (BMI)

BMI = Weight (kg) / (Height in m)²

Measure of body fat

Normal: 18.5-24.9

Key Terms

SA Node

Pacemaker of the heart

AV Node

Delays impulse, allows atrial contraction

Hemoglobin

Oxygen carrier in blood

Nephron

Functional unit of the kidney

Neuron

Functional unit of nervous system

Hormone

Chemical messenger in endocrine system

Mnemonics

🔑 "A B C D" - Heart Valves

A = Aortic valve, B = Bicuspid (Mitral) valve, C = Chordae tendinae, D = Deoxygenated (Pulmonary valve)

🔑 "SAD PANIC" - Excretory Organs

S = Skin, A = Anus (Large intestine), D = Diaphragm (Lungs), P = Pancreas, A = Alimentary canal (Liver), N = Nose (Lungs), I = Intestine (Large), C = Colon (Kidneys)

🔑 "PRIME" - Endocrine Glands

P = Pineal, P = Pituitary, R = Reproductive, I = Islets (Pancreas), M = Mammary (Thyroid, Parathyroid), E = Endocrine (Adrenal)

🧬 Genetics Key Formulas & Terms

Important Formulas

Hardy-Weinberg Equilibrium

p² + 2pq + q² = 1

p = frequency of dominant allele, q = frequency of recessive allele

p + q = 1

Linkage Distance

Recombination Frequency (%) = (Recombinants / Total) × 100

Measure of distance between genes

1% RF = 1 cM (centimorgan)

Chi-Square (χ²) Test

χ² = Σ (O - E)² / E

Used to test goodness of fit

Compare with critical value

DNA Content in Cells

2n = Diploid (Somatic), n = Haploid (Gametes)

DNA content: 2C in G1, 4C in G2/M

C = DNA content of haploid genome

Inbreeding Coefficient

F = (1/2)ⁿ

Probability of identical alleles

n = number of generations

Key Terms

Allele

Alternative form of a gene

Homozygous

Same alleles (AA or aa)

Heterozygous

Different alleles (Aa)

Phenotype

Observable trait

Genotype

Genetic makeup

Codominance

Both alleles expressed (e.g., AB blood group)

Incomplete Dominance

Blending of traits (e.g., Mirabilis jalapa)

Pleiotropy

One gene affects multiple traits

Polygenic Inheritance

Multiple genes affect one trait

🌿 Ecology Key Formulas & Terms

Important Formulas

Population Density

D = N / A

N = number of individuals, A = area

Density per unit area/volume

Population Growth (Exponential)

dN/dt = rN

r = intrinsic growth rate, N = population size

Unlimited resources

Population Growth (Logistic)

dN/dt = rN (1 - N/K)

K = carrying capacity

Limited resources

Net Reproductive Rate

R₀ = Σ lₓ · mₓ

lₓ = survivorship, mₓ = fecundity

R₀ > 1 = growing population

Biomass Energy Transfer (10% Law)

Energy transferred = 10% of previous trophic level

Lindeman's law

Only ~10% energy moves to next level

Species Richness

Species Richness = Number of species in a community

Shannon-Wiener Index: H = -Σ p_i ln p_i

Higher H = greater diversity

Key Terms

Ecosystem

Biotic + Abiotic components interacting

Niche

Role of an organism in its ecosystem

Habitat

Place where organism lives

Biodiversity

Variety of life in an ecosystem

Succession

Gradual change in community over time

Biogeochemical Cycle

Cycling of elements through biotic and abiotic

Food Chain

Linear flow of energy

Food Web

Interconnected food chains

🧪 Biotechnology Key Formulas & Terms

Important Formulas

PCR: DNA Amplification

N = N₀ × 2ⁿ

N = final copies, N₀ = initial copies, n = cycles

Exponential amplification

Restriction Enzyme Recognition

4ⁿ = possible recognition sequences

n = number of bases in recognition site

6-base cutter: 4⁶ = 4096 sites

Gene Cloning Efficiency

Transformation Efficiency = Colonies / μg DNA

Measure of cloning success

Expressed as cfu/μg DNA

Restriction Fragment Length

Fragment Size = Total DNA / Number of fragments

Size of DNA fragments after digestion

Used in RFLP analysis

Key Terms

Plasmid

Circular DNA used as cloning vector

Recombinant DNA

DNA from two different sources combined

PCR

Polymerase Chain Reaction - amplifies DNA

Gel Electrophoresis

Separates DNA fragments by size

Cloning Vector

Carrier DNA for gene transfer (e.g., plasmid, phage)

DNA Fingerprinting

Identifying individuals based on DNA patterns

CRISPR-Cas9

Gene editing technology

⚡ Quick Revision Must-Know Facts

Human Body Facts

Blood pH: 7.35-7.45

Body temp: 37°C, Heart rate: 72/min

Cell Cycle Duration

Average: ~24 hours

G1: 12h, S: 6h, G2: 4h, M: 2h

DNA & Chromosomes

Human: 46 chromosomes (22 pairs + XX/XY)

Each chromosome has 1 DNA molecule

Blood Groups

A, B, AB, O

Rh factor: + or -

Plant Hormones

Auxin, Cytokinin, Gibberellin, ABA, Ethylene

Growth regulators

Animal Hormones

Insulin, Glucagon, Adrenaline, Thyroxine

Endocrine system regulators

Quick Memory Aids

🔑 "PASS" - Plant Growth Hormones

P = Promoters (Auxin, GA, Cytokinin), A = Abscisic acid (inhibitor), S = Stomata (ABA closes stomata), S = Senescence (Ethylene promotes)

🔑 "FLAT" - Phases of Cell Cycle

F = First Gap (G1), L = Longest phase (G1), A = Synthesis (S), T = Third phase (G2), M = Mitosis

🔑 "CASH" - Cell Division Stages

C = Chromosomes condense (Prophase), A = Arrangement at equator (Metaphase), S = Separation of chromatids (Anaphase), H = Halved (Telophase)

🔑 "HOMES" - Great Lakes (not for NEET, but fun!)

H = Huron, O = Ontario, M = Michigan, E = Erie, S = Superior