Describe the four classes of biological molecules explaining what subunits comprise them and what their functions in the body are.

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ncchemist eNotes educator| Certified Educator

The four major classes of biomolecules are carbohydrates, proteins, nucleic acids, and lipids.  They are discussed below:

Carbohydrates are composed of saccharides, or sugars.  These sugars can link together to form polysaccharide polymers for complex carbohydrates.  Carbohydrates are used by cells for energy production.

Proteins are composed of long polymers of amino acids.  Proteins can take highly complex shapes that aid in their functionality.  Proteins are used as enzymes to catalyze chemical reactions.  They are also used as structural material and for highly specific binding and molecular recognition (protein-protein interactions).

Nucleic acids are composed of long chains of nucleotides which, in turn, are composed of a phosphate, a sugar, and a base group.  Nucleic acids include DNA and RNA and are used for storing genetic information and protein biosynthesis.

Lipids are composed of fatty acids which are long hydrocarbon chains that are highly non-polar and hydrophobic.  They help comprise cellular membranes and are involved in insulating body temperature and maintaining water content.  Steriods can also be classified as lipids and they are chemical messengers that help control various cell activities.

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