3. LIPIDS Important for: Important for: Membranes Membranes Hormones Hormones Energy storage Energy storage Everyday: Everyday: Fats – solid at room temperature Fats – solid at room temperature Oils – liquid at room temperature Oils – liquid at room temperature Three types, all contain C, H, O Three types, all contain C, H, O Triacylglycerols Triacylglycerols Phospholipids Phospholipids Steroids Steroids

4. FUNCTIONS of TRIGLYCERIDES Energy storage Energy storage Insulation Insulation

5. Fatty Acids Long Chain hydrocarbons with a carboxyl terminus

6. TRIACYLGLYCEROLS Comprise 3 fatty acids attached to a molecule of glycerol Comprise 3 fatty acids attached to a molecule of glycerol Triesters Triesters Formed by dehydration synthesis – esterification, forming an ester linkage

7. Saturation Fatty acids can be SATURATED Fatty acids can be SATURATED Contain no C=C double bonds Contain no C=C double bonds e.g. Stearic acid (C18), Palmitic acid (C16) e.g. Stearic acid (C18), Palmitic acid (C16) OR UNSATURATED OR UNSATURATED Contain a C=C double bond Contain a C=C double bond Oleic acid (C18, 1 double bond) Oleic acid (C18, 1 double bond) OR POLYUNSATURATED OR POLYUNSATURATED Contain more than one C=C double bond Contain more than one C=C double bond e.g. linoleic acid (C18, 3 C=C double bonds) e.g. linoleic acid (C18, 3 C=C double bonds) Unsaturation introduces KINKS

8. The degree of saturation determines physical properties The degree of saturation determines physical properties Saturated fats pack closely together (no kinks) – solid at room temp. Saturated fats pack closely together (no kinks) – solid at room temp. »Most animal fats are saturated – hard Unsaturated fats have kinks in them, cannot pack closely together(kinks) – liquid at room temperature Unsaturated fats have kinks in them, cannot pack closely together(kinks) – liquid at room temperature »Most plant fats are unstaurated Saturation

9. TRIACYGLYCEROLS Triglycerides are simple or mixed Triglycerides are simple or mixed –Simple all three fatty acids are the same –Mixed – contains more than one type of fatty acid

10. In 1860, Fredrick Walton invented linoleum the home floor covering. In 1860, rubber manufacturer Fredrick Walton invented linoleum the floor covering used in Victorian homes. Three years later, Walton received an English patent for linoleum. Walton was inspired to invent linoleum as a cheap substitute for a more expensive rubber composition called Kamptulicon. He got the idea from observing the skin on oxidized linseed oil that forms on paint. Linoleum is made of linseed oil, pigments, pine rosin and pine flour. Linoleum is manufactured by oxidizing linseed oil and adding the other ingredients to form a thick mixture called linoleum cement. The name linoleum comes from the Latin word, linum, which means flax, and oleum, which means oil. Linoleum was later replaced in popularity by vinyl floor coverings of the 1960s.vinyl Linoleum was later perfected by Scottish flooring manufacturer Michael Nairn, who introduced the inlaid patterning that linoleum is known for. Together with fellow inventor Fredrick Thomas Palmer, Fredrick Walton later invented Anaglypta and Lincrusta. Anaglypta and Lincrusta are two forms of Victorian-era embossed home wall coverings. Lincrusta is made of a linseed oil mixture and Anaglypta is made from cotton pulp.

11. PHOSPHOLIPIDS Phospholipids Phospholipids Almost exclusively found in cell membranes Almost exclusively found in cell membranes Naturally form bilipid layer Naturally form bilipid layer choline choline serine ethanolamine Low molecular weight alcohol combined here Based on glycerol structure Based on glycerol structure Two fatty acid chains (esterified) Two fatty acid chains (esterified) 3 rd alcohol group binds to a phosphate group and an alcohol e.g. choline 3 rd alcohol group binds to a phosphate group and an alcohol e.g. choline

12. Membrane Formation Phospholipids are amphipathic Phospholipids are amphipathic –Hydrophobic (tail), & hydrophilic (head) Naturally form bilipid layers Naturally form bilipid layers Because membranes contain lipids, Fat soluble molecules e.g steroid hormones can pass straight through them. Receptors for these hormones found in cytosol.

13. Phospholipids –Phosphatidyl ethanolamine (cephalins) Most common phospholipids in animal & plant membranes Most common phospholipids in animal & plant membranes –Phosphatidyl choline (lecithins)

14. Steroids Structural variety derived from variation in side chains

15. Cholesterol Essential component of membranes (eukaryotes, not prokaryotes) – Essential component of membranes (eukaryotes, not prokaryotes) – Precursor for: Precursor for: –Adrenocorticoid hormones (e.g. cortisone), –Sex hormones (e.g. oestrogen, testosterone) –Bile acids (e.g. deoxycholic acid)

16. Glycolipids Lipids with a carbohydrate moiety attached Lipids with a carbohydrate moiety attached