20739527
Description
Flashcards by Marissa Alvarez, updated more than 1 year ago
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Created by Marissa Alvarez
almost 5 years ago
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| Question | Answer |
| Concepts to understand | What is a lipid? Major lipid functions: cell membrane, energy, protection, signaling, storage, and transport Recognize major lipid building blocks Backbones of complex structures that hold these pieces together Precursor molecules Major types of lipids formed by combining and/or modifying our building blocks. |
| LIPIDS Lipid molecules contain relatively large ___ fragments ____: do not dissolve in water but do dissolve in non-polar solvents •Do ___ form polymers but held together by hydrophobic forces | hydrocarbon Hydrophobic NOT |
| Lipids Major FUNCTIONS Cell membrane: -____ components -Regulation of membrane _____ - Membrane ____ (cholesterol, saturation of fatty acids) -Membrane flexibility Energy storage: Fuel RESERVES of a typical 70-kg man Triacylglycerols (adipose tissue): 100'000 kcal (30-40 days) Glycogen (liver): 600 kcal (1 day) Glucose (blood): 40 kcal Protein (muscle): 25,000 kcal | Structural permeability fluidity Order of fuel reserve use: triacylglycerols -> glycogen -> glucose -> protein |
| Lipids Major FUNCTIONS Protection: -Protection of internal organs -____ insulation -Electric insulation (____ in myelin cells) -Skin oil Cell signaling: There is a wide spectrum of signal molecules (e.g., steroid hormones) Storage and transport: -Fat-soluble ___ -____ transport fats in blood plasma And it tastes good too ... | Thermal sphingolipids vitamins Lipoproteins |
| Overview of all types of Lipids These types are formed from a few rearranged functional units, like in a LEGO game. |
Image:
Lipids (binary/octet-stream)
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| Simplest building block: FATTY ACIDS (FA) FA: R-COO(-) Acyl group: RCO- Hydrocarbon tail: R >100 FAs that vary in: -Length -# of double bonds -position of double bonds -branching -Mostly hydrophobic -Polar carboxyl group --> acid |
Image:
F As (binary/octet-stream)
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| SATURATED FAT -__ double bonds in the hydrocarbon tail -FAs that are saturated have the ____ number of H atoms. | NO maximum |
| UNSaturated Fat Fatty acids that have ___ ___ in their hydrocarbon tails (R) are UNsaturated. -One double bond = ____ FA -Many double bonds = _____ FA | double bonds monounsaturated polyunsaturated |
| Melting point = temperature at which solid fat becomes ___ Cis = 13 degrees Celsius Trans: 45 degrees Celsius Linear molecules pack ___ *This concept is important for membrane fluidity (need Cis b/c fats stay liquid under physiological conditions.) | liquid tightly |
| Rotation is ___ around the double bond with cis and trans configurations __ conformation is prevalent in FA (even though ___ is often more stable) *Trans fat may occur at ___ concentrations | forbidden Cis trans low |
| The problem of dietary trans fats: -UNsaturated fat (vegetable oil) can be ____ to become partially saturated, and therefore solid --> longer shelf life, spreadable "butter." A certain fraction of trans molecules is inevitably produced. Trans fats are known to be ____ : increase "bad" cholesterol | hydrogenated unhealthy |
| Melting Point in FA's -___ with carbon chain length -Decreases with addition if a __ ___ | Increases double bond |
| GLYCEROL -is the backbone of many fat molecules -The three hydroxyl groups can form up to ___ linkages | three |
| Glycerol + ester linkages with FAs give _______ Come from vegetable oils, milk products, meat Body-produced from ___ calories we consume. ROLE: energy depot -However, high levels may cause ___ When glucose levels are poorly controlled in diabetes, ___ levels may increase indicating the problem. |
Triacylglycerol (or triglyceride)
extra
disease
triglyceride
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Tg (binary/octet-stream)
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| Glycerophopholipids are ___ molecules They have both hydrophobic and hydrophilic groups. The lipid composition of different membranes __ throughout the cell. | amphipathic varies |
| Sphingosine (another backbone) -is similar in structure to glycerol but has a derivative (___ group) -However, it is a backbone for a new lipid class: ______ Sphingomyelin is abundant in the ___ ___ system. | amino Sphingolipids central nervous |
| ______ : glycosphingolipid in which one monosaccharide residue is attached toa ceramide | Cerebroside |
| Compare: Phospholipid versus Glycosphingolipid | |
| ___ = oligosaccharide chain is attached to a to a cerebroside (a cerebroside + more sugars) | Ganglioside |
| Cholesterol -precursor to ___ Membrane fluidity: -At WARM temperatures cholesterol ___ movement of phospholipids -At COOL temperatures it maintains ___ by preventing tight packing -Can be both made & consumed | steroids (such as steroid hormones) restrains fluidity |
| Steroids are derivatives of ___ including: -Steroid ___, such as androgens (m) & estrogens (f), cortisol -Bile ___ (facilitate absorption of lipids in the intestine) | cholesterol hormones salts |
| Isoprenoid Class -Consists of steroids, lipid vitamins, & tr terpenes -Squalene = precursor of most steroids | |
| Reconnecting to Lecture 10 A, D, E, and K are the lipid vitamins; contain long ___ chains. They belong to the ___ class. These fat-soluble vitamins are stored in fat tissues and the ___. Vitamin A deficiency is the leading cause of preventable childhood ___ in developing countries. Vitamin A is the precursor for a light-sensitive pigment in rhodopsin. | hydrophobic isoprenoids liver blindness |
| Eicosanoids are ____ molecules that play roles in inflammation, fever induction, blood pressure regulation, and clotting, & the immune response. Aspirin ___ synthesis of prostaglandin E2 | signal inhibits |
| ___ are esters of long-chain fatty acids and long-chain alcohols |
WAXES
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Waxes (binary/octet-stream)
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| Lipids summary: • Largely hydrophobic -May have a polar group => amphiphilic -3 Fatty Acids + glycerol => ____ {2 Fatty Acids + phosphate-X}+ glycerol => ______ Glycerophospholipids are major components of cell membranes Sphingolipids have a different (____, not glycerol) backbone Sphingolipids are also part of the cell membrane Steroids. Cholesterol modulates membrane ___ Terpenes Waxes Eicosanoids: signal molecules that are locally formed near membranes Vitamins | Triglyceride Glycerophospholipid sphingosine fluidity |
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