CIE iGCSE Biology-12.2 Aerobic respiration- Study Notes- New Syllabus
CIE iGCSE Biology-12.2 Aerobic respiration- Study Notes – New syllabus
CIE iGCSE Biology-12.2 Aerobic respiration- Study Notes -CIE iGCSE Biology – per latest Syllabus.
Key Concepts:
Core
- Describe aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy
- State the word equation for aerobic respiration as:
glucose + oxygen → carbon dioxide + water
Supplement
- State the balanced chemical equation for aerobic respiration as:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Aerobic Respiration
Definition
Aerobic respiration is a series of chemical reactions that take place inside cells, where oxygen is used to break down nutrient molecules (like glucose) to release energy.
⚙️ Where It Happens
- Occurs in the mitochondria of cells.
- Takes place in plants, animals, fungi, and most other living organisms.
🔁 Word Equation:
\text{Glucose} + \text{Oxygen} \rightarrow \text{Carbon dioxide} + \text{Water} + \text{Energy}
\]
🧪 Balanced Chemical Equation:
\[
\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{energy (ATP)}
\]
⚡ Purpose of Aerobic Respiration
Provides ATP (energy) needed for:
- Muscle contraction
- Active transport
- Cell division
- Protein synthesis
- Nerve impulse transmission
- Maintaining body temperature (in warm-blooded animals)
🧠 Key Features
- Requires oxygen
- Efficient – releases a large amount of energy per glucose molecule
- End products (CO₂ and water) are non-toxic and easily removed from the body
Aerobic respiration is the oxygen-dependent process in cells that breaks down glucose to release energy for life activities.
Word Equation for Aerobic Respiration
Equation:
\text{Glucose} + \text{Oxygen} \rightarrow \text{Carbon dioxide} + \text{Water}
\]
📌 Meaning of Each Component:
| Substance | Role in Respiration |
|---|---|
| Glucose | Main fuel – energy-rich sugar from food |
| Oxygen | Reacts with glucose to release energy |
| Carbon dioxide | Waste gas – exhaled from the lungs |
| Water | By-product – used or removed by the body |
⚡ Key Points:
- This reaction releases energy for the cell (in the form of ATP).
- Happens in the mitochondria of most cells.
- Used for movement, growth, repair, and other life functions.
- Only occurs when oxygen is available.
Aerobic respiration is the process where glucose is broken down using oxygen to release energy, producing carbon dioxide and water.
Balanced Chemical Equation for Aerobic Respiration
✅ Equation:
\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}
\]
📌 Explanation of Each Term:
| Formula | Substance | Role in Respiration |
|---|---|---|
| C₆H₁₂O₆ | Glucose | Main fuel (comes from food) |
| O₂ | Oxygen | Taken in through breathing, helps break down glucose |
| CO₂ | Carbon dioxide | Waste gas – exhaled |
| H₂O | Water | Waste/by-product – used or removed by body |
🧠 Why It’s “Balanced”:
The number of atoms on both sides of the equation is equal:
- Carbon atoms: 6 (from glucose → 6 CO₂)
- Hydrogen atoms: 12 (from glucose → 6 H₂O)
- Oxygen atoms: 18 total
– 6 in O₂ (reactant), 6 in CO₂ (product), 6 in H₂O (product)
⚡ What the Reaction Does:
- Releases energy (ATP) used for:
- Movement (muscle contraction)
- Growth and repair
- Active transport
- Nerve impulses
- Temperature regulation
Aerobic respiration breaks down glucose in the presence of oxygen to produce carbon dioxide, water, and energy.