Term
| List seven roles of lipids |
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Definition
1. Energy storage
2. Bilayer structure
3. Cofactors, signaling molecules
4. Pigments
5. Hydrophobic anchors for proteins
6. Chaperones for membrane protein folding
7. Emulsifying agents |
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Term
| How long are fatty acid chains? |
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Definition
| 4 to 36 carbons long (C4–C36), usually an even number since it's derived from acetate |
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Term
| If there is a double bond in fatty acid, where is it usually? |
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Definition
| Between C‑9 and C-10 (Δ9), and other double bonds in polyunsaturated fatty acids generally Δ12 and Δ15 |
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Term
| How does chain length affect solubility and melting point? |
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Definition
| A longer chain will be less soluble and have a higher melting point |
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Term
| In what form are most fatty acids found in blood? |
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Definition
As ester or amide derivatives—
lacking the charged carboxylate group, these derivatives are even less soluble in water than the free fatty acids
(Another option is bound to albumin) |
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Term
| How would you create (solid) margarine from (liquid) vegetable oil? Is this healthier? |
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Definition
| Partial hydrogenation (reduces some of their double bonds to single bonds but converts others to unhealthy trans double bonds) |
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Term
| How can cellular lipids be extracted, separated, and identified? |
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Definition
1. Homogenized in chloroform/methanol/water
2. Lipid now in organic phase
3. Chromatography
4. NaOH/methanol to cleave off fatty acids
5. Mass spectrometry |
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Term
| Briefly describe how mass spectrometry works |
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Definition
| Bombardment with a stream of electrons is used to volatize the molecule,ionize it (to carry a positive charge on the N atom) and fragment it by breaking C-C bonds. The mass spectrometer separates the parent ion (M+) and charged fragments according to their mass/charge ratio (m/z). |
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Term
| Describe a biological wax |
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Definition
| fatty acid + long chain alcohol |
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Term
| List some physical properties and functions of waxes |
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Definition
-Esters of long chains fatty acids bound to long chain alcohols
-Higher melting point than triacylglycerol
-Storage fuel for plakton
-Waterproofing |
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Term
| Describe the structure of cholesterol |
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Definition
-Steroid nucleus with three six-rings and one five-ring
-Alkyl side chain
-Hydroxyl group makes it polar |
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Term
| List the roles of sterols |
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Definition
-Membrane structural lipid
-Cardiac glycosides (digoxin, digitoxin, ouabain)
-Steroid hormones
-Emulsifiers (bile acids) |
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Term
| List six steroid hormones derived from cholesterol |
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Definition
1. Testosterone
2. Estradiol
3. Cortisol
4. Aldosterone
5. Prednisolone
6. Prednisone |
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Term
| What is the only way to eliminate excess cholesterol? |
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Definition
| Synthesis and subsequent excretion of bile acids in the feces |
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Term
| List three functions of bile acids |
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Definition
1. Solubilize cholesterol
2. Emulsification of dietary fat
3. Facilitate absorption of fat soluble vitamins |
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Term
| What are the four fat soluble vitamins? |
|
Definition
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Term
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Definition
| Compounds essential to the health of humans and other vertebrates that are generally not synthesized by the animals and, therefore, must be derived from the diet |
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Term
| How can unibuqinone, dolichols, and fat-soluble vitamins be made in the body? |
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Definition
| By condensation of multiple ispoprene units |
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Term
| What is the role of vitamin A and D? |
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Definition
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Term
| List the steps to form the active hormone form of Vitamin D |
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Definition
1. Cholesterol
2. Dehydrocholesterol + UV light in skin
3. Cholecaliceferol
4. Steps in liver/kidney
5. 1,25-dihydroxyvitamin D3 |
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Term
| How can vitamin A be formed endogenously? |
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Definition
| By enzymatic cleavage of β-carotene |
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Term
| What are the roles of vitamin A hormone? |
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Definition
| Regulating gene expression (particularly in development of epithelial tissue) and as the visual pigment (11-cis-retinal) of the vertebrate eye |
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Term
| What is the structure and function of vitamin E (tocopherol)? |
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Definition
Membrane-associated, hydrophobic lipids with a substituted aromatic ring and a long isoprenoid side chain
The aromatic ring reacts with and destroys most free radicals. |
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Term
| What is the function of vitamin K? |
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Definition
| The aromatic ring undergoes a cycle of oxidation and reduction in the activation of prothrombin, a blood clotting enzyme |
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Term
| How does Warfarin (Coumadin) work? |
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Definition
| Blocks the action of vitamin K1 in activation of prothrombin to reduce risk of embolism of a thrombus |
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Term
What is the function of ubiquinone?
(C'mon, you should know this.) |
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Definition
| Ubiquinone (coenzyme Q) is a lipophilic electron acceptor used as an electron carrier in oxidative phosphorylation. |
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Term
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Definition
| Isoprenoid alcohols that act as sugar carriers during assembly of bacterial cell walls and during the addition of polysaccharide units to proteins and lipids of eukaryotes |
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Term
| List two ether lipids that are found in membranes |
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Definition
-Alkyl ether lipids
-Plasmalogens (platelet-activating factor) |
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Term
| List two chloroplast membrane lipids |
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Definition
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Term
| Describe the structure of a glycerophospolipid |
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Definition
Like triacylglyceride, but with one fatty acid replaced by a phosphate-containing head group
All links joined by an ester bond |
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Term
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Definition
| A glycerophospholipid missing a fatty acid |
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Term
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Definition
| A glycerophospholipid missing the phosphate-containing head group |
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Term
| What is phopshotidylcholine associated with? |
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Definition
| Blood clotting and apoptosis |
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Term
| What is phopshotidylinositol-4,5-bisphosphate associated with? |
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Definition
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Term
| What is cardiolipid (a glycerophospholipid) associated with? |
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Definition
| Mitochondrial membrane and the electron transport chain |
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Term
| What is another name for phosphatidylcholine? |
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Definition
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Term
| Describe the structure of sphingolipids |
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Definition
| Like triacylglycerol, but the backbone is sphingosine (alcohol) instead of glycerol and there is a C-3 head group |
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Term
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Definition
A sphingosine with a fatty acid (generally a saturated fatty acid) attached in amide linkage to the amino group at the C-2 position
Structurally similar to diacylglycerol |
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Term
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Definition
| Ceramide with a phosphocholine head group |
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Term
| What are glycolipids made of in animal cells? |
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Definition
| Sphingolipids with mono- or oligosaccharide head groups. |
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Term
| Compare and contrast a phosphotidylcholine and a sphingomyelin affect on fluidity in a membrane |
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Definition
Phosphatidylcholine: one tail unsaturated
Sphingolipid: both saturated, more rigid |
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Term
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Definition
| A sphingolipid with a di-, tri-, or tetra-saccharide head group |
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Term
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Definition
| A sphingolipid with a complex oligosaccharide head group |
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Term
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Definition
| A sphingolipid with a single sugar head group |
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Term
| How is glucosylcebroside synthesized? What can it be used for? |
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Definition
By condensation of ceramine with UDP-glucose in the golgi
(All sphingolipids are synthesized in the golgi)
Glucosylcerebroside is a precursor for synthesis of more complex sphingolipid |
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Term
What harmful substances bind directly to globoside on cell surfaces?
What harmful substance binds directly to gangliosides on cell surfaces? |
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Definition
Glucoside- Shiga toxin and verotoxin
Ganglioside- Cholera, tetanus, botulism toxin |
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Term
| Describe the rates of sphingolipid creation |
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Definition
| Constant, because they are being constantly removed from the membrane though endocytosis or other degradation |
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Term
| What diseases can result from impaired degradation of sphingolipids |
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Definition
Generalized gangliosidosis, Tay-Sachs, Nrimann-Pick disease, Gaucher's (don't memorize)
Many neuron diseases, genetic diseases |
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Term
| What does buildup of ganglioside cause in neurons? |
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Definition
Up-regulation of inflammation in microglial cells, leading to massive neuronal cell death
Fatal within 3 years |
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Term
| What drug can treat Gaucher's disease and possibly other ganglioside buildup diseases? |
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Definition
| Genz-112638, an analog that inhibits glucosylceramide synthase |
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