Download Poster

1 . 3
N U T R I T I O N
The Function of Food: Growth, Repair, Energy
ELEMENTS IN FOOD:
WATER
Bimolecular units: The elements in
food combine in different ratios to form
different food components
Common Elements: Carbon (C) ,
Hydrogen (H) ,Oxygen (O), Nitrogen
(N), Phosphorus (P), Sulphur (S)
Salts of: Sodium (Na), Magnesium
(Mg), Chlorine (Cl), Potassium (K),
Calcium (Ca)
Trace elements : Iron (Fe), Copper
(Cu), Zinc (Zn)
Properties of water:
• Gives cells their shape
• Transports materials
• A universal solvent
• A medium for metabolism
CARBOHYDRATES
Contain elements: C, O, H.
General formula: Cx(H2O)y
Structural role: cellulose forms part of
the cell wall
Metabolic role Source of energy for
metabolism
Types of Carbohydrate
Monosaccharides e.g. glucose
Disaccharides e.g. sucrose
Polysaccharides e.g. cellulose
MINERALS
Plants need Magnesium to make
chlorophyll and calcium for the cell
walls
Animals need iron to make
haemoglobin and calcium for
healthy bones.
ENERGY TRANSFER
REACTION
FATS
Contain elements: C, O, H.
Different ratio to carbohydrates – have
more oxygen
Fats are solid at room temperature
Oils are liquid at room temperature
Structural role: protect the body
organs
Metabolic role Source of energy for
metabolism
Triglycerides: made up of three Fatty
acids and one Glycerol
Phospholipids formed when one
fatty acid of a lipid molecule is
replaced by a phosphate group
Anabolic reactions: Small
molecules are built up into large
ones, using energy e.g.
photosynthesis
Catabolic reactions: large
molecules are broken down into
smaller ones, energy is released
e.g. respiration
PROTEINS
Contain elements: C, O, H, N
They sometimes contain P, S
They are made up of amino acids
Structural role: they join with
phospholipids to form the cell
membrane
Metabolic role: all enzymes are
proteins and they control the cells
chemical reactions
VITAMINS
Vitamin
Type
Source
Function
Deficiency
C
Water
soluble
Lemons
Connective tissue
formation
Scurvy
D
Fat
soluble
Cod-liver oil
Absorb calcium
Rickets