92 Elements occurring naturally in nature Only 25 needed to build living organisms Common elements found in cells – classified into 3 groups
Main elements
Trace elements
Ultra-Trace elements
INORGANIC COMPOUNDS
ORGANIC COMPOUNDS
Do not contain Carbon (C)
Contain Carbon (C)
Smaller & simpler than OC
Macromolecules
Found in cells water, acids, alkalis and mineral salts.
4 main groups
Produce energy during respiration Store energy – glycogen (animals) , starch (plants) Polysaccharides
– supporting structure – cellulose (plants) - chitin (animals)
Compounds – C, H, O, P and N 2 types – DNA (deoxyribonucleic acids) , RNA (ribonucleic acids) Basic units of nucleic acids – Nucleotides (nitrogen base, sugar and phosphate group) Importance - Store genetic information - Stable storage - Easy to duplicate for transmission
Importance - Provide structure & shape (collagen , keratin) - Movement - muscles - Form defense system - antibodies - Form enzymes - Form membrane & carrier proteins - Form hormones - Form haemoglobin - Energy store
Importance - Solvent - Transport - Coolant – absorbs excess heat from cells - Insulator – maintain narrow range of temperature change - Reactant – condensation & hydrolytic - Give structure & support – hydrostatic , turgor pressure