Term
| What is the definition of a lipid? |
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Definition
| A macronutrient soluble in organic solvents such as chloroform, ether and acetone |
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Term
| What are the types of lipids? |
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Definition
| Simple, Compound, derived, and ethyl alcohol |
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Term
| Name types of simple lipids |
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Definition
| Fatty acids, triacylglycerols, waxes, diacylglycerols and monocylglycerols |
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Term
| Name types of compound lipids |
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Definition
| Phospholipids, glycolipids, lipoproteins |
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Term
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Definition
| derivatives such as sterols and straight chain alcohols obtained by hydrolysis and still possess lipid properties |
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Term
| Describe basic fatty acid structure |
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Definition
| composed of a straight hydrocarbon chain (hydrophobic) terminating with a carboxylic group (hydrophillic) |
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Term
| What are the two essential fatty acids? |
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Definition
| linoleic acid and alpha linolenic acid |
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Term
| What is the importance of the two essential fatty acids (EFAs)? |
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Definition
| They are essential because the human body does not produce it because the body lacks delta 12 and delta 15 desaturases (enzymes) |
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Term
| Describe pathway of arachidonic acid production, two key enzymes |
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Definition
| linoleic acid-->gamma linolenic acid-->eicosatrienoic acid-->arachidonic acid. Delta 12 and delta 15 desaturases are enzymes needed |
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Term
| Polyunsaturated fats of nutritional interest may have how many double bonds? |
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Definition
| as many as 6 double bonds |
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Term
| Carbon-carbon double bonds in the cis form result in: |
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Definition
| kinking of the fatty acid to a U-shape |
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Term
| What lipids are a major component of cell and organelle membranes? |
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Definition
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Term
| Triacylglycerols with unsaturated fatty acids tend to be ______ at room temperature? |
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Definition
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Term
| Cholesterol serves as a precursor for _______? |
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Definition
| bile acids, steroid sex hormones (estrogen, progesterone, androgens), and vitamin D |
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Term
| Sphingomyelins serve what function? |
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Definition
| they are important in the nervous system, specifically a constituent of the myelin sheath. |
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Term
| What is (are) the role(s) of Prostaglandins and thromboxanes? |
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Definition
| Help lower blood pressure, diuresis, blood platelet aggregation, effects on gastric secretions, stimulation of smooth muscle contraction |
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Term
| What is (are) the role(s) of leukotrienes? |
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Definition
| Potent biological actions-they contract respiratory, vascular, and intestinal smooth muscles |
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Term
| What is the difference between a saturated and unsaturated fatty acid? |
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Definition
| There are no double bonds in saturated fatty acids and at least one double bond in the unsaturated fatty acids |
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Term
| Why does the body synthesize and utilize sterols/steroids? |
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Definition
| sterol is an essential component of cell membranes (esp. nerve tissue). Sterols are precursors to steroids. Both are important in many metabolic reactions. |
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Term
| Why does the body synthesize and utilize phospholipids? |
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Definition
| structural components to cell membranes, anchoring membrane proteins, intracellular signaling and act as second messengers in hormone stimulation |
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Term
| Why does the body synthesize and utilize glycolipids? |
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Definition
| Their principal role is structural. Occur in sheaths of nerves in brain and nerve tissue. |
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Term
| What is the carrier for long-chain dietary fatty acids in circulation? |
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Definition
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Term
| What is a function of Apolipoprotein? |
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Definition
| stimulate certain enzymatic reactions to regulate metabolic functions. Also, stabilize lipoproteins as they circulate in the aqueous environment of the blood. |
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Term
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Definition
| A small spherical dispersion of polar emulsified lipid and bile. Makes it possible for FAs and other lipids that are polar to be absorbed into the cytosol of the intestinal cell for chylomicron formation |
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Term
| TAG, cholesterol, and phospholipid absorption and digestion process. |
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Definition
| enter the stomach in tact-->TAGs are hydrolyzed in stomach (others enter the intestine) --> TAGs, lipids, bile salts form micelles and acted upon with pancreatic enzymes-->short-chain FFAs move into portal circulation with albumin--> |
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Term
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Definition
| The protein portion of the lipoprotein. They help lipoproteins be soluble in blood. |
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Term
| What is the definition of lipoprotein? |
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Definition
| Conjugated proteins consisting of simple proteins and lipids. Play an important role in transporting lipids. |
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Term
| Describe similarities and differences of chylomicrons and VLDLs. |
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Definition
chylomicrons - small lipoprotein w/TAGs, fat-soluble vitamins, cholesterol, and phospholipids. synthesized in intestinal mucosa cells from lipd digestion.
VLDLs - small lipoprotein synthesized in liver and used to transport TAGs to peripheral tissues. Slightly more dense than chylomicrons. |
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Term
| What is the action of Lipoprotein Lipase? |
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Definition
| Aids in intravascular hydrolysis of chylomicrons which occurs on the endothelial cell surface of small non-hepatic blood vessels. |
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Term
| What is the action of Hormone Sensitive Lipase? |
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Definition
| hydrolyzes stored TAGs to FFAs particularly in adipose tissue (intracellular) |
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Term
| Explain the importance of the liver in lipid metabolism. |
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Definition
| Synthesis of lipoproteins from endogenous lipids and apoproteins. Synthesizes new lipids from nonlipid precursors (amino acids and carbs). It can cataboize exonegous lipids from chylomicron remnants. (page 148) |
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Term
| Explain the importance of the adipose tissue in lipid metabolism. |
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Definition
| Adipose absorbs TAG and cholesterol from chylomicrons through the action of lipoprotein lipase. (page 149) |
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Term
| What is the lipoprotein of greatest quantity present in the blood during fasting? |
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Definition
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Term
| Which lipoprotein is the major carrier of cholesterol away from tissues for excretion by the liver? |
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Definition
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Term
| To what cells does LDL have a high affinity to bind to? |
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Definition
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Term
| Prostaglandins exhibit what range of physiological actions? |
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Definition
| they only affect cells in which they are synthesized. They effect the immune system, visual development, and fatty acid synthesis in the cells they are in. |
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Term
| What are the two pathways for eicosanoid synthesis? |
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Definition
| The cyclic pathway-formation of prostaglandins and thromboxanes. AND the linear pathway which produces leukotrienes. |
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Term
| What hormone inhibits hormone sensitive triacyglycerol lipase found in adipose tissue cells? |
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Definition
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Term
| What organ provides the major site for lipoprotein formation from endogenously produced lipids? |
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Definition
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Term
| What is a major risk factor for cardiovascular disease? |
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Definition
| High levels of circulating LDL |
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Term
| What is the mechanism by which orlistat decrease caloric consumption ? |
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Definition
| by inhibiting pancreatic lipase activity which restricts hydrolysis of triacylglycerols. |
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Term
| What enzyme is inhibited by drug therapy to decrease serum cholesterol? |
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Definition
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Term
| Trans unsaturated FAs elevate serum LDL while decreasing HDL and are therefore likely to: |
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Definition
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Term
| Carnitine is the carrier molecule for what system? |
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Definition
| Mitochondrial membrane transport of FAs and their CoA derivatives. |
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Term
| beta oxidation in the mitochondria produces _______? |
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Definition
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Term
| Cholesterol is synthesized from? |
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Definition
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Term
| Leukotrienes are hormone-like substances made from? |
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Definition
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Term
| What is the most important unsaturated FA serving as a precursor for eicosanoids that antagonize those made from an omega-6 fatty acid precursor? |
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Definition
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Term
| What is the role of cholesterol and cholesteryl esters on artherosclerosis? |
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Definition
| They are both major components of fatty plaque. Cholesteryl esters promote the inflammatory process. |
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Term
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Definition
| hydrolysis occurs in the body through the activity of lipoprotein lipase (vascular and non-hepatic) and intracellular lipase in liver and adipose tissue. The glycerol portion is used for energy in the liver and other tissues with the activity of glycerokinase. Glycerol is converted to glycerol phosphate and enters the glycolytic pathway. |
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Term
| Are most FAs metabolized composed of even or odd number of carbon atoms? |
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Definition
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Term
| Can FAs with odd numbered carbon atoms be metabolized? |
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Definition
| Yes. Beta oxidation occurs with a residual propionyl CoA. Oxidation of propionyl CoA requires use of biotin and b12 in a coenzymatic role. Succinyl CoA is formed and can be converted to glucose. Therefore the odd numbered carbon FAs are glucogenic among all the FAs. |
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Term
| Why are ketone bodies important during starvation? |
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Definition
| They provide brain and muscle energy during starvation. |
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Term
| Explain ketone body formation: |
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Definition
| ketone bodies are formed when there is an accumulation of acetyl CoA due to a reduction in oxaloacetate availability. |
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