🧬 IGCSE Biology Formula Sheet 2025

Complete Cambridge IGCSE Biology (0610) 2025 Syllabus Formula Reference Guide

Cambridge IGCSE Biology 0610 Free Download

Essential IGCSE Biology Formulas & Equations

Master your IGCSE Biology exams with our comprehensive formula sheet covering all essential formulas and equations for Cambridge IGCSE Biology (0610) 2025 syllabus. This reference guide includes photosynthesis, respiration, circulation, genetics, ecology, and more.

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Cambridge IGCSE™ Biology (0610)

Formula & Equation Sheet - 2025 Syllabus

🌱 1. Photosynthesis

Word equation:

carbon dioxide + water → glucose + oxygen

Requires light and chlorophyll

Balanced symbol equation:

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Light and chlorophyll above arrow

Limiting factors:

Light intensity, carbon dioxide concentration, temperature

Affect rate of photosynthesis

🫁 2. Respiration

Aerobic respiration:

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy

Energy released as ATP

Anaerobic respiration (animals):

glucose → lactic acid (+ ↓ energy)

In muscle cells

🔥 3. Energy Content in Food (Calorimetry)

Energy released:

E = m × c × ΔT

E = energy (J), m = mass of water (g), c = 4.2 J/g°C

Energy per gram of food:

E / mass of food burned (g)

J/g - Used in food energy experiments

🌊 4. Diffusion, Osmosis & Active Transport

Rate of diffusion:

Rate ∝ (surface area × concentration difference) / diffusion distance

Applies to gases and solutes

Osmosis:

Movement of water through a partially permeable membrane

From high to low water potential

Active transport:

Movement against concentration gradient

Requires energy (ATP)

❤️ 5. Circulation

Cardiac output:

Cardiac output = Stroke volume × Heart rate

cm³/min or L/min

Pulse rate:

number of beats / time

bpm (beats per minute)

🫁 6. Breathing and Gas Exchange

Breathing rate:

number of breaths / time

breaths/min

Minute ventilation:

Tidal volume × Breathing rate

cm³/min

🍽️ 7. Human Nutrition

BMI (Body Mass Index):

BMI = weight (kg) / (height (m))²

Used to assess obesity

Energy per gram (food test):

m × 4.2 × ΔT / mass of food

Alternative calorimetry formula

⚗️ 8. Enzymes

Rate of enzyme reaction:

Rate = 1 / time taken

e.g., time for starch to disappear

Optimum conditions:

pH and temperature

Enzyme activity affected by denaturation

🧬 9. Genetics

Genotype:

Genetic constitution

e.g. Bb

Phenotype:

Observable characteristics

e.g. brown eyes

Genetic ratio:

number with one phenotype / number with another

Derived from Punnett square

Probability of inheritance:

no. of desired outcomes / total outcomes

Used in genetic crosses

🌿 10. Ecology

Population density:

Population density = number of organisms / area (m²)

organisms/m²

Percentage cover:

(area covered by species / total area) × 100

Energy transfer efficiency:

(energy at higher trophic level / energy at lower trophic level) × 100%

Mean per quadrat:

total individuals / number of quadrats

individuals/quadrat

🧠 11. Nervous System

Reaction time:

Reaction time = distance fallen / acceleration due to gravity

In ruler drop tests, indirectly measured

Reflex arc:

stimulus → receptor → sensory neuron → relay neuron → motor neuron → effector

Not numerical but process flow

🔄 12. Excretion & Homeostasis

Water balance:

water gain = water loss

Maintained by kidneys

Body temperature regulation:

via negative feedback

Qualitative understanding

📊 13. Summary of Key Units & Constants

Specific heat capacity of water:

c = 4.2 J/g°C

Used in calorimetry calculations

Average human body temperature:

37°C

Normal body temperature

Normal atmospheric pressure:

1.01 × 10⁵ Pa

Standard atmospheric pressure

Volume conversion:

1 dm³ = 1000 cm³

Useful for volume calculations

Energy transfer efficiency:

%

Percentage units

📚 How to Use This Biology Formula Sheet

🧬

Understand the Concepts

Don't just memorize formulas - understand the biological processes behind each equation to apply them correctly in different contexts.

🧪

Practice Calculations

Work through practice problems involving calorimetry, population density, and energy transfer to build confidence with these formulas.

📝

Know Your Units

Pay attention to units in calculations. Converting between cm³, dm³, and other units is crucial for accurate answers.

🔬

Apply to Experiments

Connect these formulas to practical experiments you've done or will do, such as food tests, enzyme investigations, and ecological surveys.

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