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Carbohydrates As Fuel
Carbohydrates are organic compounds that serve as a major source of chemical energy for living organisms.
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Carbohydrates As Fuel
Foods such as bread, rice and potatoes contain carbohydrates.
The body can break many carbohydrates down into simpler sugars such as glucose.
Glucose can then be used in respiration to release energy.
Recommended for Class 9
Carbohydrates As Fuel
Definition
Carbohydrates are organic compounds that serve as a major source of chemical energy for living organisms.
Formula / Key Relation
A simplified aerobic respiration equation is:
`C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy`
Glucose contains stored chemical energy.
Cells release this energy through controlled biochemical reactions.
Glucose:
`C₆H₁₂O₆`
Aerobic respiration:
`C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy`
Carbohydrates As Fuel — Advanced
Carbohydrates are not literally “burned” inside cells like fuel in a flame. Instead, they are oxidised through enzyme-controlled pathways.
The released energy is captured partly in usable chemical forms, including ATP, rather than being released entirely as heat.
Common Mistakes
Common Mistakes
- Mistake
Do not say carbohydrates are the only energy source in the body.
- Mistake
Lipids and, under some conditions, proteins can also contribute energy.
- Mistake
### Sticky Notes
- Mistake
CARBOHYDRATES
- Mistake
Main role:
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ENERGY
- Mistake
Glucose:
- Mistake
`C₆H₁₂O₆`
- Mistake
Respiration:
- Mistake
Glucose + O₂
- Mistake
→ CO₂ + H₂O + energy
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
Carbohydrates provide chemical energy, often after digestion into glucose that can be oxidised during respiration.
Carbohydrates are major biological fuels. Many dietary carbohydrates are broken down into glucose, which cells can oxidise during respiration. The simplified aerobic equation is `C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy`. Respiration occurs through controlled enzyme-catalysed steps, and some of the released energy is captured in ATP. Carbohydrates are important energy sources but are not the only molecules capable of supplying energy.
- Definition
- Carbohydrates are major biological fuels. Many dietary carbohydrates are broken down into glucose, which cells can oxidise during respiration. The simplified aerobic equation is `C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy`. Respiration occurs through controlled enzyme-catalysed steps, and some of the released energy is captured in ATP. Carbohydrates are important energy sources but are not the only molecules capable of supplying energy.
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Practice
PQ
Q1. What is the main role of carbohydrates?
PQ
Q2. What sugar is commonly used in respiration?
PQ
Q3. Write the glucose formula
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Q4. What gas is required for aerobic respiration?
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Q5. What are the main products?
Exam Practice
EQ
Q1. Explain why carbohydrates are called biological fuels
EQ
Q2. Write the aerobic respiration equation
EQ
Q3. Explain the role of glucose
EQ
Q4. Explain why cellular respiration is not ordinary burning
EQ
Q5. State the importance of ATP
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.