Lipid Chemistry and Metabolism

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Lipid chemistry, structure, and function. Biological membranes
Kristina Redd
Flashcards by Kristina Redd, updated more than 1 year ago
Kristina Redd
Created by Kristina Redd over 7 years ago
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Question Answer
Unsaturated fat is a _____ fat. Good
Saturated and trans fat and cholesterol are all _____ fat. Bad
What are lipids: hydrophilic or hydrophobic? Hydrophobic
Are lipids polar or nonpolar? Very nonpolar
What form of energy do lipids take in the diet? dietary triglycerides
What form of energy do lipids take in energy stores? adipose tissue glycerides
What are significant advantages of triglycerides? Highly reduced (energy-rich), compact for energy storage, good insulator
What are specific amphipathic lipids? phospholipids, sphingolipids, cholesterol
What are examples of signaling molecules? 2nd messenger systems; eicosanoids; steroid hormones
Name 4 fat-soluble vitamins. A (vision), D (bones/teeth), E (anti-oxidant), K (blood clotting)
What are the building blocks of most lipids? Fatty Acids
CH3(CH2)16COOH Stearic Acid
Identify the lipid and the shorthand. Steric Acid 18:0
What are all fatty acids ionized at? physiological pH; pKa <5
Identify alpha, beta, and omega.
What does omega-# indicate? The double bond closest to the methyl end is # carbons from the w end.
What does "methylene-interrupted" mean? The configuration contains more than one cis double bond. Always 3C between C=C bonds.
If the shorthand for FA is 18:2w6, what dies it look like and what is the name?
Virtually all FA are esterified to 3-C glycerol as what? Triglycerides (energy stores), phospholipids (membranes)
What is the destination for "free" FAs (complexed w/ albumin)? Transported from adipose to other tissues for [ox]
How are some FAs oxidized for energy? Into the FA~CoA form
How are FAs critical to life? energy storage for use during fasting
What is the correlation between melting point and chain length? MP increases as chain length increases
What are the two primary physiological functions of lipids? hydrophobicity and fluidity
A lipid must be long enough that the carbon chain outweighs its ____ end. Polar
True/False: The melting points of fatty acis increase as saturation increases. True. MP for stearic acid (18:0) > MP for linolenic acid (18:3)
True/False: The MP for saturated fatty acids is typically below body temperature. False. Saturated fatty acids have a MP far above body temp to prevent them from melting.
What two components of membrane lipids and adipose tissue triglycerides are regulated to maintain appropriate fluidity? chain length and degree of unsaturation
The last carbon of a double bond is always considered as the ____ in shorthand nomenclature. omega
What form do all C=C double bonds take: cis or trans? cis
What characteristics make trans-FA bad? no kinks and tightly packed
Why are "kinks" in fatty acids good for membranes? less packing and increase fluidity
T/F: Increasing saturation also increases oxidation. False. Increasing saturation = higher MP = solid = less oxidation = prolonged shelf life
Which is good cholesterol and which is bad cholesterol? HDL-cholesterol = good LDL-cholesterol = bad
What does trans-FA do to LDL and HDL cholesterols? Increase LDL and decrease HDL
What is the chemical reaction when an alcohol (glycerol) joins a COOH (fatty acid)? ester (glyceride)
Identify this fatty acid. Triglyceride
What makes plant oils better than animal fats when cooking? Vegetable oils and polyunsaturated FAs are more unsaturated than animal fats (except tropical oils). There also isn't cholesterol in plant oils.
_____ are esters of long-chain alcohols and long-chain FAs. Waxes
What are examples of waxes? cetyl alcohol & palmitic acid
What is special about cetyl-palmitate? It is a principal component of spermaceti, pearly white translucent wax highly prized as fragrance.
What are other common waxes in nature? lanolin (sheep wool) bee's wax (honey combs)
What are 3 ways of assessing obesity? BMI (height vs. weight), skin-fold thickness, and body density
How do you calculate calories when considering exercise? Calculate calories supplied by endogenous protein, fat, and carbohydrate during the starvation period
What is the respiratory quotient (RQ)? What is the equation and how is it measured? RQ is measured to determine which fuel source (carbs, fat, protein) is being utilized. RQ = ∆CO2/-∆O2 Fuel and RQ: Carbs = 1.00, Fat = 0.71, Protein = 0.81
What is saponification? Alkaline hydrolysis of fat to make soap. It allows synthetic detergents to be amphipathic.
What is the chemical process of saponification?
What makes phospholipids a vital component of membranes? - glycerol backbone (like TG) - 2 FA in ester linkages - phosphate + X (choline, ethanolamine, serine, inositol) - amphipathic (amphi = both)
What is the THE defining component of biological membranes?
Name this phospholipid. Phosphatidylcholine (PC)
Name this phospholipid. Phosphatidylethanolamine (PE)
Name this sterol.* Cholesterol
Name this sterol.* Glycocholate
Name this sterol. Testosterone
What is it about the amphipathic nature of PL and glycolipids that make it vital to life? glycolipids = hydrophobic tails + polar heads --> ability to form micelles in water lipid bilayer is 2 molecule thick and is a framework for all bio membranes.
What is a liposome? A sphere w/ inner aqueous compartment (similar shape to a micelle)
How do proteins diffuse? Laterally, unless restricted by other cell components
What is coined as "lipid rafts" in a plasma membrane? microdomains
What two carbohydrate chains are specific only to the extracellular portion of a plasma membrane? glycolipids and glycoproteins
What are special proteins (such as PL, cholesterol, and glycolipids) called when embedded in lipid bilayer? integral proteins
Identify the plasma membrane.
What is a potent "local" hormone derived from AAs in PL membranes via phospholipase A2? eicosanoids
Arachidonic acid can develop into these two eicosanoids (cell-specific synthetases) using cyclooxygenase as enzyme. prostaglandins & thromboxanes
Arachidonic acid can develop into this eicosanoid using lipoxygenase as enzyme. Leukotriene
What are a few side effects of eicosanoids? pain, inflammation, vasoconstriction/dilation, ulcers, heart attack
What enzyme is used for a phospholipid in a cell membrane to develop into an Arachidonic Acid? PLase A2
How does aspirin/vioxx/celebrex decrease an eicosanoid from progressing into more detrimental forms? It cuts off cyclooxygenase after it has developed into arachidonic acid so that it can't become a prostaglandin or a thromboxane.
How do hormones act? Steroid hormones? Hydrophilic hormones?
What specific omegas are required in the diet? w6 and w3
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