1.1 Chemical elements are joined together to form biological compounds

Water, Carbohydrates, Lipids, Proteins

Carbohydrates- Monosaccharides

Carbohydrates are organic compounds which contain carbon hydrogen and oxygen.
The basic unit of carbohydrate is monosaccharide.
Monosaccharides are monomers (single sugar molecules).
2 monosaccharide form a disaccharide and many monosaccharide molecules form a polysaccharide.

List the types of monosaccharide and explain their function

Triose (3)- Important in metabolism, triose sugars are intermediates in the reactions of respiration and photosynthesis.
Pentose (5)- constituents of nucleotides eg. deoxyribose in DNA, ribose in RNA, ATP and ADP.
Hexose (6)- Hexose sugars includes glucose, galactose and fructose. Glucose is a source of energy in respiration, carbon-hydrogen and carbon-carbon (C-H, C-C) bonds are broken to release energy which is transferred to make ATP.

Describe LIPIDS

Lipids organic compounds made of carbon, hydrogen and oxygen.
Triglycerides are the common type of lipid and fats and oils.

Lipids have low proportion of oxygen compared with carbohydrates. Triglycerides are non-polar so they are insoluble in water, but they can dissolve in organic solvents such as chloroform, ether and ethanol.

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