Term
| What are the major functions of lipids? |
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Definition
Major component of cell membranes
Major dietary source of energy
Used to produce Steroid Hormones and Prostaglandins
Signalling
absorption and transport of fat soluble vitamins/drugs
Protect vital organs and insulate the body from temperature extremes |
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Term
| Lipid Water interactions are decided primarily by what forces? |
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Definition
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Term
| What are the two types of lipids? |
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Definition
| Polar (some hydrogen bonding) and Non-Polar (no hydrogen bonding) |
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Term
| What are the major Polar Lipids? |
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Definition
| Fatty Acids, Phospholipids/sphingolipids, and Cholesterol |
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Term
| What is the major role of Polar lipids? |
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Definition
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Term
| What are the major Non-Polar lipids? |
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Definition
| Triglycerides and Cholesterol Esters |
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Term
| What is the main function of non-polar lipids? |
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Definition
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Term
| What is the most common metabolic fatty acid? |
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Definition
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Term
| What is a saturated fatty acid? |
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Definition
| A fatty acid with no double bonds |
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Term
| What are the major components of a fatty acid? |
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Definition
| Water soluble head group (typically acid) and hydrocarbon tail |
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Term
| What is the alpha carbon of a fatty acid? |
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Definition
| the first carbon after the water soluble head |
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Term
| What is the beta carbon of a fatty acid? |
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Definition
| the second carbon after the water soluble head group |
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Term
| What is the omega carbon? |
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Definition
| Final carbon of a fatty acid |
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Term
| What defines an unsaturated fatty acid? |
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Definition
| presence of a double bond |
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Term
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Definition
| Found on a an unsaturated fatty acid. Denotes the presence of a double bond (Delta 4 carbon would mean double bond between 4-5) |
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Term
| Cis double bonds do what to fatty acids? |
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Definition
| Cis double bonds introduce a "kink" to the fats and lower the melting temperature |
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Term
| A shorter carbon chain gives changes what chemical property in fatty acids? |
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Definition
| Solubility. The shorter the chain the more soluble the fatty acid |
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Term
| What are the major functions of fatty acids? |
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Definition
major energy source
membrane lipid synthesis (phospho/sphingo)
production of storage lipids (TG)
Precursors for prostaglandin synthesis |
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Term
| Why does the food industry create trans-fatty acids? |
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Definition
To protect unsaturated fatty acids from oxidation
done via hydrogenation |
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Term
| What are the major components of a phospholipid? |
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Definition
Two hydrophobic tails attached to glycerol
a phosphate group attached to glycerol
water soluble head group attached to the phosphate |
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Term
| What are the R groups of a phospholipid? |
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Definition
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Term
| How are sphingolipids different from phospohlipids? |
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Definition
| head group is derived from serine instead of glycerol |
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Term
| How does Cholesterol interact with water? |
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Definition
| Cholesterol is mostly hydrophobic but does make some hydrogen bonds utilizing its OH group. |
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Term
| What is the function of Cholesterol? |
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Definition
| Cholesteral can regulate the fluidity of a membrane, important for maintaining physiologic functionality |
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Term
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Definition
| polar lipid derivatives of cholesterol |
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Term
| What is the difference between Cholesterol and Cholesterol Ester? |
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Definition
| Cholesterol Ester has lost the slight polarity of the OH group by instead attaching a carbon chain. This is done for storage of Cholesterol |
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Term
| As phospholipid concentrations increase in an aqueous environment, what are the various structures that can form? |
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Definition
| Emulsion -> Micelle -> Bilayer -> Bilayer Membrane -> Multilamellar Lipsome (synthesized in labs for drug delivery) |
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Term
| How are non-polar lipids mobilized through the body? |
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Definition
| By wrapping them in polar lipids via the micelles (forming vesicles) |
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Term
| How is fatty acid and cholesterol brought into the membrane? |
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Definition
| While equal preference exists between traversing and re-entering the vesicle, membrane proteins exist to drive preference towards the cell |
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Term
| How do Triglycerides and Cholesterol-esters cross into the membrane from the vesicle? |
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Definition
| The don't. Instead they are converted into fatty acids/cholesterol and then reconverted once they enter the cell |
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Term
| What are the key enzymes in the transformation of lipids? |
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Definition
| Acyltransferases and Lipases |
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Term
| What is the function of Acyltransferase? |
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Definition
| Acyltransferase converts fatty acids into triglycerides via esterification |
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Term
| What is the function of Lipase? |
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Definition
| Lipase makes Triglycerides into Fatty Acids via lipolysis |
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Term
| Why are triglycerides ideal for energy storage? |
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Definition
Hydrophobic (stay in cell)
Highly Reduced
Not very reactive
Not very soluble (do not mess with cell osmolarity) |
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