F.4 Biology

organic substance is carbon containing compound , some of them may also contain hydrogen ,oxygen,nitrogen,halogen or sulphur beside carbon.
e.g . carbohydrates , fats, proteins and nucleic acid in organism . However, inorganic substance is not a carbon containing compound, e.g mineral and water in organism .

2006-11-24 19:04:25 補充：
there are some exceptional case :carbon dioxide, carbon monoxide,carbonates and hydrogencarbonates even contain carbon , but they are not regard as organic compound but inorganic.

An organic substance is a substance which has carbon and hydrogen in it, if it has the highest possible number of hydrogen for the given number of carbon, it is called a saturated organic compound.
An inorganic substance could have either carbon or hydrogen in it but not both.

有機物含碳,
而無機則不含碳,除左二氧化碳,一氧化碳,碳酸鹽和碳酸氫鹽,都是無機物!

有機物質用火燒會取得碳
無機物質用火燒不會取得碳