Food
Nutrients are used for
ELEMENTS IN FOOD
Biomolecules are chemicals made inside a living thing
4 major biomolecules are
6 common elements in food
5 elements dissolved in salts
3 trace elements (tiny amounts)
CARBOHYDRATES
Elements: Carbon, Oxygen and Hydrogen in ratio Cx(H2O)y where x=y, twice as much hydrogen
Structure: Monosaccharides (smallest carbohydrate, single sugar unit, sweet to taste, soluble in water e.g. glucose),
Disaccharides (two sugar units, soluble in water, sweet yo taste e.g. sucrose=glucose + fructose)
Polysaccharides (many sugar units, not soluble in water, not sweet to taste e.g. starch)
Functions: Structural (cellulose forms plant cell walls)
Metabolic (glucose gives energy in respiration)
Tests: Starch (add iodine, red to blue/black indicates starch)
Reducing Sugars (dissolve food in water, add benedicts solution and heat, blue to brick red indicates reducing
sugars
PROTEINS
Elements: Carbon, Hydrogen, Oxygen, Nitrogen and sometimes sulphur and phosphorus
Structure: Amino Acids -> Peptides -> Polypeptides -> Proteins
20 common amino acids
Folded into complex 3D shapes
Fibrous (little/no folding. Form long fibres. Strong and tough e.g. keratin in hair and nails)
Globular (lots of foldings. Form round shapes e.g. enzymes
Sources: Meat, fish, eggs, milk, peas and beans
Functions: Structural (Keratin in hair and nails)
Metabolic (enzymes, antibodies, hormones)
Test: Dissolve food in water, add sodium hydroxide (colourless) and copper sulfate (blue). Blue to Purple indicates
protein
LIPIDS
Fats (solid) and lipids oils (liquid) at room temperature
Elements: Carbon, Oxygen, Hydrogen (in different ratio to carbohydrate)
Structure: Basic unit is a triglyceride (1 glycerol and 3 fatty-acids)
Phosphate is a fat like substance where one fatty acid is replaced by a phosphate group
Sources: Butter, oil, cream, fat on meat
Fuctions: Structural Lipids (food/ energy store in plants and animals. Provides twice as much energy as carbohydrates)
Stored lipids (insulation, protection or organs, phospholipids form cell membranes
Test: Rub sample (butter) on brown paper and permanent translucent stain appears indicates fat
VITAMINS
Are biomolecules needed in tiny amounts (not made in body)
Vitamin C (Water Soluble)
Sources: Fruits and Vegetables
Metabolic Role: forms connective tissue (skin, gums, blood vessels)
Deficiency: Scurvy (pour healing, bruising and bleeding gums)
Vitamin D (Fat Soluble)
Sources: Liver, fish oils and milk. Also when UV rays and sunlight act on are skin
Metabolic Role: Help absorption of calcium from intestines
Deficiency: Causes rickets in children and osteomalacia in adults (weak deformed brittle bones)
MINERALS
Plants: Calcium (cell walls) and Magnesium (chlorophyll)
Animals: Calcium (bones and teeths) and Iron (red pigment in haemogolbin)
WATER
Essential for life for 3 main reasons
Importance for water for living things include:
- Energy
- Chemical Reactions
- Growth and Repair
ELEMENTS IN FOOD
Biomolecules are chemicals made inside a living thing
4 major biomolecules are
- Carbohydrates
- Lipids
- Proteins
- Vitamins
6 common elements in food
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Phosphorus
- Sulphur
5 elements dissolved in salts
- Sodium
- Magnesium
- Chlorine
- Pottasium
- Calcium
3 trace elements (tiny amounts)
- Copper
- Zinc
- Iron
CARBOHYDRATES
Elements: Carbon, Oxygen and Hydrogen in ratio Cx(H2O)y where x=y, twice as much hydrogen
Structure: Monosaccharides (smallest carbohydrate, single sugar unit, sweet to taste, soluble in water e.g. glucose),
Disaccharides (two sugar units, soluble in water, sweet yo taste e.g. sucrose=glucose + fructose)
Polysaccharides (many sugar units, not soluble in water, not sweet to taste e.g. starch)
Functions: Structural (cellulose forms plant cell walls)
Metabolic (glucose gives energy in respiration)
Tests: Starch (add iodine, red to blue/black indicates starch)
Reducing Sugars (dissolve food in water, add benedicts solution and heat, blue to brick red indicates reducing
sugars
PROTEINS
Elements: Carbon, Hydrogen, Oxygen, Nitrogen and sometimes sulphur and phosphorus
Structure: Amino Acids -> Peptides -> Polypeptides -> Proteins
20 common amino acids
Folded into complex 3D shapes
Fibrous (little/no folding. Form long fibres. Strong and tough e.g. keratin in hair and nails)
Globular (lots of foldings. Form round shapes e.g. enzymes
Sources: Meat, fish, eggs, milk, peas and beans
Functions: Structural (Keratin in hair and nails)
Metabolic (enzymes, antibodies, hormones)
Test: Dissolve food in water, add sodium hydroxide (colourless) and copper sulfate (blue). Blue to Purple indicates
protein
LIPIDS
Fats (solid) and lipids oils (liquid) at room temperature
Elements: Carbon, Oxygen, Hydrogen (in different ratio to carbohydrate)
Structure: Basic unit is a triglyceride (1 glycerol and 3 fatty-acids)
Phosphate is a fat like substance where one fatty acid is replaced by a phosphate group
Sources: Butter, oil, cream, fat on meat
Fuctions: Structural Lipids (food/ energy store in plants and animals. Provides twice as much energy as carbohydrates)
Stored lipids (insulation, protection or organs, phospholipids form cell membranes
Test: Rub sample (butter) on brown paper and permanent translucent stain appears indicates fat
VITAMINS
Are biomolecules needed in tiny amounts (not made in body)
Vitamin C (Water Soluble)
Sources: Fruits and Vegetables
Metabolic Role: forms connective tissue (skin, gums, blood vessels)
Deficiency: Scurvy (pour healing, bruising and bleeding gums)
Vitamin D (Fat Soluble)
Sources: Liver, fish oils and milk. Also when UV rays and sunlight act on are skin
Metabolic Role: Help absorption of calcium from intestines
Deficiency: Causes rickets in children and osteomalacia in adults (weak deformed brittle bones)
MINERALS
- Form body structures such as bone and cement between cell walls
- Make soft body parts like muscles
- Play a role in forming cell and body fluids such as tears and saliva
- Form biomolecules such as haemoglobin (iron) and chlorophyll (magnesium)
Plants: Calcium (cell walls) and Magnesium (chlorophyll)
Animals: Calcium (bones and teeths) and Iron (red pigment in haemogolbin)
WATER
Essential for life for 3 main reasons
- Liquid in which all metabolic reactions takes place
- Provides basis for transport systems in organisms
- Environment in which many organisms live
Importance for water for living things include:
- It is a major component of cytoplasm and body fluids (75%-90% of mass of cells)
- Good solvent. Many molecules dissolve in water. This allows chemical reactions to take place. Materials can also be transported in water e.g. blood/xylem and phloem
- Participate in metabolism/ chemical reactions
- Water can easily pass in or out of biological membranes
- Good absorber if heat energy (slow to heat up and cool down). Maintains temperature despite temperature changes around it. Provides stable temperature for living things and their reactions