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Food is needed for
- Energy (respiration)
- Growth of new cells (mitosis)
- Repair of existing cells
- Also supplies materials and energy for :
- Metabolism
- Continuity
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What is food made up
- 6 chemical elements (CHONPS)
- Salts (SMP)
- Trace elements (ICZ)
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What are biomolecules
Biomolecules are small substances that make up living things
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List of biomolecules
- Carbohydrates
- Lipids
- Proteins
- Vitamins and Minerals
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Carbohydrates: elements and ratio
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3 types of carbohydrate
- Monosaccharides
- Disaccharides
- Polysaccharides
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What are monosacharrides
Single sugar molecules
Example: Glucose and fructose
Source: fruit
Metabolic role
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What are disaccharides
Two sugar units
Example: Lactose and maltose
Source: dairy
Metabolic role
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What are polysaccharides
Many sugar units
Example: Starch, cellulose and chitin
Source: potatoes, cell wall, insect exoskeletons
Structural role
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Lipids elements and ratio
Carbon, hydrogen and oxygen
Not in fixed ratio
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Triglyceride is..
A lipid unit with 3 fatty acids and one glycerol
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Phospholipid is
Two fatty acids, phosphate and glycerol
Found in cell membrane
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Proteins consist of
Carbon, hydrogen, oxygen and nitrogen
Sometimes sulphur and phosphorous
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Sources of protein
Lean meat, fish, eggs
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Protein chain
Amino acid > peptide bond > polypeptide > protein
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Vitamins are
- Small chemicals
- Needed in small amounts
- Cannot be produced
- Involved in metabolic process
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Source and function of Vitamin C
Source: citrus fruits
Function: healthy skin, teeth, gums
Water soluble
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Source and function of Vitamin B
Source: cereal
Function: metabolism
Water soluble
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Source and function of Vitamin A
Source: green veg/carrots
Function: eyesight, night vision
Fat soluble
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Source and function of Vitamin D
Source: dairy, sunlight
Function: bone development
Fat soluble
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Vitamin deficiency C
- Scurvy
- Rotting teeth
- Bleeding gums
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Vitamin deficiency D
- Rickets
- Brittle bones
- Bowed legs
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Animal minerals
Calcium, bone growth and development
Iron, need to form haemoglobin
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Plant minerals
Calcium, form cell wall
Nitrogen, used to make proteins
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Anabolic reaction
Small > big
Energy required
Example: photosynthesis and joining two strands of DNA
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Catabolic reaction
Big > small
Energy released
Respiration
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Structural roles of carbohydrate
Cellulose: used to form cell walls
Chitin: insect exoskeletons
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Structural role of lipids
Insulation and waterproofing
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Structural role of protein
Myosin - fibre that builds muscles
Keratin - makes hair and nails
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Metabolic roles of carbohydrates
Glucose - energy
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Metabolic roles of lipids
Energy
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Metabolic roles of proteins
Enzymes
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Test for sugar
Chemical: Benedicts reagent
Heat: yes
Colour change: blue to brick red
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To test for lipids
Chemical: oil
Heat: no
Colour change: translucent spot
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To test for starch
Chemical: iodine
Heat: no
Colour change: yellow to blue black
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To test for protein
Chemical: sodium hydroxide and copper sulfate
Heat: no
Colour change: blue to purple
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