Biochemistry Part VBiochemistry Part V

LipidsLipids

LipidsLipids

A class of organic molecules that are insoluble A class of organic molecules that are insoluble in waterin water

There are 3 major groups of lipidsThere are 3 major groups of lipids TriglyceridesTriglycerides PhospholipidsPhospholipids SteroidsSteroids

TriglyceridesTriglycerides

Include fats, oils, and waxesInclude fats, oils, and waxes Consist of 3 fatty acids attached to a glycerol Consist of 3 fatty acids attached to a glycerol

moleculemolecule Hydrocarbons with a Hydrocarbons with a

carboxyl group (-COOH)carboxyl group (-COOH)

at one end of the chainat one end of the chain

(Saturated)

Monounsaturated

Polyunsaturated

PhospholipidsPhospholipids Looks just like a lipid except that one of the Looks just like a lipid except that one of the

fatty acid chains is replaced by a phosphate fatty acid chains is replaced by a phosphate group (-POgroup (-PO33

2-2-)) An additional chemical group (R) might also An additional chemical group (R) might also

be attachedbe attached AmphipathicAmphipathic

Hydrophilic heads (phosphates)Hydrophilic heads (phosphates) Hydrophobic tails (lipids)Hydrophobic tails (lipids)

Provide the foundation for cell membranesProvide the foundation for cell membranes

SteroidsSteroids

Characterized by a backbone of 4 linked Characterized by a backbone of 4 linked carbon ringscarbon rings

Examples:Examples: CholesterolCholesterol Some HormonesSome Hormones

TestosteroneTestosterone EstrogenEstrogen

Illegal Steroids????Illegal Steroids????

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