Proteins (elements, examples of catabolic & anabolic reactions)
Trace elements, functions for food & water
Vitamins (water and fat-soluble, examples)
Minerals (functions in plants and animals)
Food tests
Important Concepts
Trace Elements
Examples: Iron, Copper, Zinc
Functions: Essential in tiny amounts
Chemical Elements in Lipids
Common Elements: Carbon, Hydrogen, Oxygen
Basic Unit: Three fatty acids + glycerol
Metabolic Pathways
Respiration: Catabolic pathway (breaks down glucose into CO2 and water)
Carbohydrates
Polysaccharide: Many monosaccharides connected
Storage Polysaccharide in Animals: Glycogen (found in liver)
Main Structural Polysaccharide in Plants: Cellulose (found in cell walls)
Reasons for Food
Energy
Growth & Repair of Tissues
Ratio in Carbohydrates
Ratio of Hydrogen to Oxygen: 2:1
Role of Lipids
Structural in Cells: Cell membrane
Metabolic: Provides energy
Vitamins
Fat-Soluble Example: Vitamin D
Water-Soluble Example: Vitamin C
Examples of Minerals
Calcium: Strengthens bones and teeth
Magnesium: Found in chlorophyll, helps photosynthesis
Iron: Found in hemoglobin, helps transport oxygen
Water
Functions: Solvent, used for transport
Percentage in Human Cells: ~70%
Food Tests
Protein: Biuret test (uses sodium hydroxide and copper sulfate)
Reducing Sugar: Benedict's/Fehling's solution (brick red color indicates presence)
Fats: Brown paper test
Elements in Proteins
Common Non-Metallic Element: Sulfur
Metabolic Role: Enzymes (all enzymes are proteins)
Structural Role: Keratin (found in hair and nails)
Differences Between Biomolecules
Triglycerides vs Phospholipids: Phospholipids contain two fatty acids, a phosphate, and glycerol. Triglycerides contain three fatty acids and glycerol.
Specific Questions from Past Papers
Catabolic Processes: Respiration, Digestion (specify as required in or out of cells)
Common Value for 'Y' in Carbohydrates: 6 (as in glucose C6H12O6)
Roles of Water & Minerals: Essential questions that often recur
Miscellaneous
Phospholipids: Found in cell membranes
Difference Between Fats & Oils: Oils are liquid at room temperature; fats are solid
Common Monosaccharides: Glucose, Fructose (formula: C6H12O6)