Chapter 9 Flashcards
What are the functions of lipids?
Structural
Energy Storage
Chemical
Protection
Vitamins
Pigments
Are biological lipids are ______
Amphipathic (have both hydrophobic and hydrophilic portions)
What makes up fatty acids?
Alkyl chains terminating in COOH
What are saturated fatty acids?
Alkyl chains that are fully reduced (no double bonds)
What are unsaturated fatty acids?
Alkyl chain that contains double bonds
Eukaryotes synthesize with ____ units
2-C
What makes odd-number fatty acids?
Bacteria
What is the code for myristic acid?
14:0
What is the code for palmitic acid?
16:0
What is the code for stearic acid?
18:0
What is the code for arachidic acid?
20:0
What is the code for oleic acid?
18:1n-9
What is the code for linoleic acid?
18:2n-9
What is the code for α-linolenic acid?
18:3n-3
What is the code for γ-linolenic acid?
18:3n-6
Unsaturated fatty acid codes give the location of the first carbon bond relative to which end?
Methyl
Which type of double bond occurs naturally in fatty acids?
Cis
Saturated fatty acids tend to be _____ at room temp
Solid (fats)
Unsaturated fatty acids tend to be ____ at room temp
Liquid (oil)
What determines the melting point of saturated fatty acids?
Chain length
Would a 16:0 fatty acid or an 18:0 fatty acid have a higher melting point?
18:0 fatty acid
The melting point increases as the chain lengthens
What determines the melting point of unsaturated fatty acids?
Number of double bonds
Would an unsaturated fat with 2 or 3 double bonds have a higher melting point?
2 Double Bonds
The melting point decreases with the number of double bonds
What are the functions of triacylglycerols?
Energy source
Describe a saponification reaction:
ester + water -> carboxylic acid + alcohol
True or False: Triacylglycerols can be made up of more than one fatty acid
True
What are adipocytes?
Specialized cells used to store fats
What is a glycerophospholipid?
1,2-diacylglycerol with phosphate on carbon 3
Glycerophospholipid is a critical component of _______
Cell membranes
If a glycerophospholipid has unsaturation, which position is more likely to be on?
2-position
Where does phospholipase A1 cut?
Carbonyl before the R1 group on a phospholipid
Where does phospholipase C cut?
Before the phosphate group on a phospholipid
Where does phospholipase D cut?
After the phosphate group on a phospholipid
What is a sphingosine?
18-carbon alcohol
What type of double bond is in sphingosone?
trans
What is a ceramide?
Fatty acid joined to sphingosine in amide linkage
Where are ceramides typically found?
Biological membranes
Where are sphingomyelins found?
Animal-cell membranes; enriched in myelin sheath
What causes Niemann-Pick Disease?
Defect in sphingomyelinase
What is a glycosphingolipid?
Ceramides with one or more sugars in a beta-glycosidic linkage at 1-hydroxyl group
What is cerebroside?
Glycosphingolipid with one sugar
What is ganglioside?
Glycosphingolipid with 3 or more sugars, one of which is sialic acid
What makes up Gm1?
D-Galactose
N-Acetyl-D-galactosamine
D-Galactose
D-Glucose
What group is attached to the D-Galactose of Gm3?
N-acetylneuraminidate (sialic acid)
What two groups are on the D-glucose of Gm3?
Stearic acid and Sphingosine
What defines Tay-Sachs Disease?
Deficient beta-hexosaminidase A
What is the function of B-Hexosaminidase?
Enzyme that hydrolyzes Gm1 to Gm2
What are the symptoms of Tay-Sachs disease?
Blindness, weakness, seizures, mental retardation
What are waxes?
Esters of long-chain alcohols with long-chain fatty acids
What is the general formula of waxes?
R1–CO–O–R2
What is carnauba wax?
Hard wax used for high-gloss finishes
What is lanolin?
Wool wax used in cosmetics
What is the function of eicosanoid?
Signaling/Hormone
What is the precursor for eicosanoids?
Arachidonic acid
What is the code for arachidonic acid?
20:4Δ5,8,11,14
What is the function of PGH2 synthase?
Catalyzes arachidonic acid to PGH2
What enzyme does aspirin inhibit?
PGH2 synthase
What is the structure of steroids?
Three 6-membered rings and one 5-membered ring fused together
What molecule is the base of steroids?
Isoprene
What is isoprene?
5C branched structure from AcetylCoA
What is cholesterol?
Precursor for all steroids in animals
What is the function of steroid hormones?
Salt balance
Metabolic function
Sexual function
What are steroid signaling receptors?
Transcription factors that move into the nucleus upon binding
Where are steroid signaling receptors?
Cytosol (inside cell)
What is the molecular order of steroid formation?
Isoprene -> Terpenes -> Steroid
What is the structure of isoprene?
H2C=CH-C(CH3)=CH2
What is transverse diffusion?
Very slow flipping from one side of the plasma membrane to the other via lipases
What is lateral diffusion?
Rapid movement down one side of the bilayer membrane
What is FRAP?
Fluorescence recovery after photobleaching
What is an integral protein?
Protein that spans the lipid bilayer
What is a peripheral protein?
Protein that sits on top of membrane surface
Why would a protein attach itself to the cell membrane?
Reduces dimensions that a molecule has to travel through to bind to the protein
What is the structure of the CXXY motif?
Cysteine -> Hydrophobic AA -> Hydrophobic AA -> Y
What amino acids in the y position of the CXXY motif give farnesylation?
Ala, Met, Ser
What amino acids in the y position of the CXXY motif give geranylgeranylation?
Leu
What is myristolation?
Myristic acid (14:0) attached to Nt amino group of Gly
What is palmitoylation?
Thioester linkage to Cys
Thioester: R1-S-CO-R2