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34 Cards in this Set
- Front
- Back
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what is the name of the special type of fat cell? what is its skill? |
adipocyte, can swell up to many times its size to store fat in a lipid droplet that can take up the entire cytoplasm |
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what is the definition of a lipid |
small or water insoluble molecules generally containing sterol, fatty acyl OR isoprenoid moieties |
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what are some identifying features of a lipid (2 features) |
1. soluble in organic solvents e.g. hexane/chloroform 2. amiphathic often - hydrophilic and phobic parts |
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what are the 7 types of lipids we covered? |
1. fatty acids, 2. TAGs, 3. glycerophospholipids, 4. sphingolipids, 5. cholesterol, 6. waxes, 7. Eicosanoids |
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define FAs |
carboxylic acid containing a long hydrocarbon chain which can be saturated (no double bonds) or unsaturated (double bonds). the number of carbons and double bonds can vary |
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describe the simple numbering method of naming and correctly name arachidonic acid |
count carbons starting from COO carbon, double bonds are given to the C closest to COO carbon and are designated cis/trans. e.g. 20:4 cis (delta)5,8,11,14 |
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describe the greek letter naming |
label second carbon alpha and continue, last carbon is omega and the double bond is counted by closest to omega carbon |
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draw and name (simple numbering) all of palmitate, stearate, oleate, linoleate, linolenate, and arachidonate |
check online or in text for answer |
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what happens to fatty acids (aka 4.5-5) in acidic pH? what about physiological pH? |
COO becomes COOH (protonated) so is named with the "ic acid" ending vs deprotonated so is named with the "ate" ending |
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describe the different melting points between trans, cis and saturated fatty acids? which would be solid-like for longest in rising temperatures? |
trans -> have intense kinks so VDW is very disrupted, have lowest melting points, liquid at room temp cis -> have kinks, not as intense but still disrupt VDW so low MP saturated -> higher melting points because strong VDW due to no disruptions down the chains |
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which type of double bond is not natural to humans? how does it get into our bodies? |
trans, they are made in the rumen of cows and are thus in dairy products that we eat, also in meat products and some are produced during partial hydrogenation (a food processing technique) |
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define TAGs |
triacylglycerols, a glycerol with 3 fatty acids chains ESTERIFIED to each the hydroxyl groups |
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draw glycerol, what types of lipids have a glycerol backbone? |
see lecture notes for image of glycerol, TAGs and glycerophospholipids have glycerol backbone |
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what occurs during the esterification of each FA onto the glycerol? |
acid(FA) + alcohol(glycerol) -> H20 + ester(linkage) |
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what is the main purpose of TAGs? what makes them so good (better than the second best) (2 main reasons)? |
used for energy storage, are completely reduced so more energy from oxidation than glycogen (gram for gram) and are hydrophobic so are stored without water (lighter and easier to store than glycogen which has hydrophilic OH group) |
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define glycerophospholipids |
have a glycerol backbone but instead of only FA chains have a phosphate PO4 group (phosphoester bond). the PO4 has an OH head group which can bind many things |
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describe the naming of glycerophospholipids |
the FA chains are ignored in the naming of the types, the group attached to PO4 is what determines the name. "phosphatidyl-" |
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draw glycerol-phosphate backbone then, draw out: phosphatidate, phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, cardiolipin |
see lecture slides for answers |
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define sphingolipids |
have a sphingosine base, have a single FA bound via AMIDE bond to amine group on (c2), has an OH head group |
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draw sphingosine |
see lecture slides for answer |
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what is ceramide? |
sphingosine with a FA via an AMIDE bond and just an OH head group - like a "parent compound" |
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what are the 3 types of head groups that can be attached? what type of linkages are formed? |
1. phosphocholine = sphingomyelin 2. single or multiple NEUTRAL sugars = cerebrosides or globosides 3. complex oligosaccharides (negative) = gangliosides |
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draw out: cerebroside, sphingomyelin, and a ganglioside |
see lecture slides |
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define cholesterol. |
its a sterol which is a type of steroid (lipid containing a core of 4 closed rings 3 with 6 carbons and 1 with 5 carbons) and an alcohol. it is only in eukaryotes and is an essential part of the membrane |
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define sterol |
steroid + alcohol, fairly planar and rigid (lie in one plane and don't move), amphipathic (OH group is only hydrophobic part) |
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define waxes |
esters of FA linked to long chain alcohol, non-polar and hydrophobic |
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define membrane |
sheet-like structure composed of lipids, usually only two molecules thick, form closed boundaries between compartments, may contain proteins |
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3 major lipid components of membranes or eukaryotes? |
1. glycerophospholipids 2. sphingolipids 3. cholesterols (not in bacteria) - also phospholipids (all membranes) |
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explain membrane permeability. |
impermeable: large molecules (proteins), and small charged or polar molecules permeable: small hydrophobic molecules due to: hydrophobicity of lipids |
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explain the Tm, Lo and Ld of membranes |
membranes have a Tm (temperature at which they are meant to live at). below this lipids are more ordered = semi-solid or gel-like = liquid ordered state. above this lipids are more disordered and it is liquid-like = liquid disordered state. Tm is the temperature where this phase transition occurs |
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how do bacteria and mammals control fluidity? |
mammals - use cholesterol bacteria - alternate the FAs attached to the phospholipids |
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explain the effect of cholesterol on fluidity at high and low temperatures. draw a fluidity vs temperature graph for membranes with cholesterol |
see online or in text for cholesterol influence. compare graph with other people |
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in general, what happens to the food we eat (aa, sugars, fats) during times of plenty? |
stored as TAGs and FA, adipocytes are filled with TAGS. acetylCoA -> FA -> TAGs |
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where does fatty acid synthesis occur? |
adipose tissue, mammary glands and liver (in the cytoplasm of these cells) other tissue cells cannot do this |
