Carbohydrate (Leaving Cert Biology): Revision Notes
📚 Revision Notes
Carbohydrate
Carbohydrates are composed of:
- Carbon
- Hydrogen
- Oxygen
General (empirical) Formula for many carbohydrates:
Ratio: 1:2:1
| Monosaccharides (1 sugar unit) | Glucose (fruit) Fructose (honey) |
|---|---|
| Disaccharides (2 sugar units) | Maltose (germinating seeds) Lactose (milk) Sucrose (table sugar) |
| Polysaccharides (3 or more sugar units) | Starch (bread, pasta, potatoes) Cellulose (vegetables, wholemeal bread) Glycogen |
Role of carbohydrates
- Structural role:
- Cellulose in plant cell walls
- Metabolic role:
- Catabolic reactions e.g. respiration
- Anabolic reactions e.g. photosynthesis (glucose synthesis)
- Energy storage:
- Stored in plants as starch
- Stored in animals (muscles and liver) as glycogen
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Structural role: involves building and supporting cell structures
Metabolic role: involves chemical reactions and processes that sustain life.
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Quick Definition Review!
Catabolic reaction: The breakdown of larger molecules into smaller molecules e.g. digestion.
Anabolic reaction: The use of smaller molecules to form larger molecules e.g. photosynthesis, protein synthesis.