Chapter 11 Flashcards
Lipids are molecules that are not ________, but are _______ in organic solvents
water soluble; soluble
What are the 5 major classes of lipids?
- Free fatty acid (common fuel)
- Triacylglycerols (storage form of fatty acids)
- Phospholipids (membrane lipids)
- Glycolipids (membrane lipids composed in part of carbohydrates)
- Steroids (polycyclic hydrocarbons w/ a variety of functions)
Name the 3 types of membrane lipids
- Phospholipids
- Glycolipids
- Cholesterol
True or False: Fatty acids are composed of hydrocarbon chains with Carbon and Hydrogen atoms
True
One end of the fatty acid hydrocarbon chain will be a ________ acid and the other end will be a _________ group
carboxylic acid; methyl group
Fatty acids are…
a) polar and soluble in water
b) nonpolar and insoluble in water
b) nonpolar and insoluble in water
Lipids comprise of about ______% of organic matter in the average human body
a) 60
b) 20
c) 40
d) 30
c) 40%
True or False: Fatty acids can only be saturated
False: Fatty acids can be saturated or unsaturated
Saturated fatty acids comprise of ______ bonds only
single
Unsaturated fatty acids have higher melting points than saturated fatty acids and comprise of only one double or triple bonds
False: Unsaturated fatty acids have lower melting points than saturated fatty acids and comprise of one or more double or triple bonds
True or False: Monounsaturated fatty acids have one double bond in their structure
True
Monounsaturated fatty acids are _______ at room temperature and ________ when refrigerated
liquid; solid
Polyunsaturated fatty acids have _________ melting points than monounsaturated fatty acids
lower
Polyunsaturated fatty acids consist of multiple _________ separated by at least one ________ group and generally remain ________ at room temp
double bonds; methylene group; liquid
Fatty acids have roles in ________, _________, ________
storing energy; cell signalling, and comprising the cell membrane
Fatty acid carbon atoms are usually numbered starting at the _________. Carbon atoms two and three are referred to as _____ and ______ carbons. The last carbon in chain is referred to as ______________
carboxy terminus; alpha; beta; omega carbon atom
Properties of fatty acids are dependent upon __________ and degree of __________
chain length; unsaturation
True or False: long chain length and presence of cis-double bonds lead to an enhancement of fluidly of the fatty acids
False: Long chain length and presence of cis-double bonds lead to an enhancement of fluidly of the fatty acids
True or False: Chain lengths in biological systems are typically in 16 or 18 carbon atom range
True
Why are cis-polyunsaturated fatty acids essential components of human diets?
They essential components to the human diet because humans cannot synthesize these. These fatty acids are precursors to a variety of hormones
With polyunsaturated fatty acids, there are multiple __________, but the bonds are separated by at least one _____________
double bonds; methylene group
True or False: Abbreviated names indicate whether a fatty acid is saturated, monosaturated, or polyunsaturated
True
Palmitic acid has ___ carbons and is _____ fatty acid (no double bond); thus, abbreviated name is ______
16; saturated; 16:0
Oleic acid has ___ carbons and is a __________ fatty acid (1 double bond at carbon-9); thus, abbreviated the name _______
18; monounsaturated; 18: 1n-9
Linoleic acid has ____ carbons and is a __________ fatty acid (2 double bonds, first double bond located at carbon-6 from omega carbon); thus, abbreviated name ______
19; polyunsaturated; 18: 2n-6
Linolenic acid has ___ carbons and is a _______fat (3 double bonds, first double bond located at carbon-3 from omega carbon); thus, abbreviated name is _______
18; polyunsaturated; 18: 3n-3
What are the three ways fatty acids can be named?
- Systematic name
- Based on number of carbons (first # in the name)
- Location of double bonds from alpha carbon (most oxidized carbon), but location of double bond is dropped
- Positions of double bonds are indicated by Δ symbol, w/ first atom of double bond indicated by a superscript number (ex. Δ9 which indicated a double bond between carbons 9 and 10) - Common name based on what someone decided to name it
- Abbreviated name
- Name starts w/ number of carbons, followed by the number of carbon-carbon double bond from ω (omega) end, than the location of the first double bond from the omega terminus (the last carbon in the chain, almost always a methyl carbon atom)
- ex. 18: 2n-9 –> this indicated that there are 18 carbons, 2 doubles bonds, and that the first double bond is located at carbon 9
List 5 saturated fatty acids
- Laurate
- Palmitate
- Arachidate
- Myristate
- Stearate
List 4 monounsaturated fatty acids and the various names for them, according to the naming system
[1]
- Palmitoleate has 16-carbons, one double bond at carbon-7 from omega carbon, (16:1n-7 in abbreviated naming system)
- Carbon-9 from alpha carbon 16:1 △9
- Systematic name is 9-Hexadecenoic acid with hexadec denoting 16-carbons, and one double bond at carbon-9 from alpha carbon
[2]
- Vaccenate has 18-carbons with one double bond at carbon-7 from omega carbon, 18:1n-7, in abbreviated naming system
- Carbon-11 from the alpha carbon, 18:1 △11
- Systematic name is 11-Octadecenoic acid with octadec denoting 18-carbons, and one double bond at carbon-11 from the alpha carbon
[3]
- Oleate has 18-carbons with one double bond at carbon-9 from the omega carbon, 18:1n-9, in abbreviated naming system
- Carbon-9 from the alpha carbon, 18:1 △9
- Systematic name is 9-Octadecenoic acid with octadec denoting 18-carbons, and one double bond at carbon-9 from the alpha carbon
[4]
- Elaidate has 18-carbons with one double bond in the trans configuration at carbon-9 from the omega carbon, 18:1n-9 trans, in abbreviated naming system
- Carbon-9 from the alpha carbon, 18:1 △9 trans
- Systematic name is 9-trans-Octadecenoic acid with octadec denoting 18-carbons, and one trans double bond at carbon-9 from the alpha carbo
List 5 polyunsaturated fatty acids and the various names for them, according to the naming system
Ex. [A]
- Linoleate 18: 2n-6
- 18:2 △9 △12
- (9,12-Octadecadienoic acid)
Ex. [B]
- Arachidonate 20:4n-6
- 20:4 △5 △8 △11 △14
- (5,8,11,14-Eicosatetraenoic acid)
Ex. [C]
- a-Linolenate 18:3n-3
- 18:3 △9 △12 △15
- (9,12,15-Octadecatrienoic acid)
Ex. [D]
- Timnodonate 20:5n-3
- 20:5 △5 △8 △11 △14 △17
- (5,8,11,14,17- Eicosatetraenoic acid)
Ex. [E]
- Cervonate 22:6n-3
- 22:6 △4 △7 △10 △13 △16 △19
- (4,7,10,13,16,19- Docosahexaenoic acid)
What are triacyclglycerols?
Triacyclglycerols are energy rich storage forms of fatty acid, formed by attachment of three fatty acid chains to a glycerol molecule
In human and animals, fatty acids are stored in _________ cells
adipose tissue
Each adipose contains a large lipid droplet in which the triacylglycerols are store
Plants store fats as…
a) nucleotides
b) seeds
c) adenosine triphosphate
d) adipose tissue
b) seeds
Why are fatty acids are an ideal storage reserve for energy?
Fatty acids are an ideal storage reserve for energy since these molecules are much more reduced than carbohydrates, thus liberating greater amounts of energy upon oxidation
Fatty acids are ________ and __________, allowing for dense storage in the absence of water molecule
hydrophobic; anhydrous
Fatty acids are stored as triacyclglycerols where ______ fatty acids are esterified to ______ molecule of glycerol. This creates a ________ molecule.
three; one; triacylgercol
What are soaps?
Soaps are sodium or potassium salts of fatty acids generated by treating triacylglycerol’s with a strong base
Examples of strong bases include sodium hydroxide (NaOH) or potassium hydroxide (KOH)
Hydrophobic ends interact of soap interact with with _____, while the Hydrophilic ends interact with ______
dirt; water
True or False: Phospholipids are important for cell membrane structure
True
True or False: Cell membrane = a single layer of phospholipids
False: Cell membrane = bilayers of phospholipids
True or False: Phospholipids are often called polar lipids
True
Phospholipids have two distinct regions: (1) ______ regions, (2) ______ regions or amphipathic molecules
hydrophobic; hydrophilic
Structures of phospholipids will include…
[1] A platform or backbone - phospholipids w/ glycerol backbone are called phosphoglycerates or phosphoglycerols. There can also be phospholipids with a sphingosine backbone
[2] Two fatty acid chains - one fatty acid is saturated, one is unsaturated
[3] A phosphate group
[4] An alcohol - could be choline, serine, or an ethanolamine
Major phospholipids are derived from ____________
phosphatide
With the amphipathic nature of phospholipids, a ____________ will form by several individual phospholipid molecules creating a membrane lipid bilayer with the _________ tail regions in interior and ______ head groups exposed to exterior aqueous environment
lamellar bilayer; hydrophobic; hydrophilic
True or False: The amphipathic nature of phospholipids can create vesicles or liposomes in aqueous solutions
True
Common phospholipids in cell membranes all contain…
[1] a glycerol backbone
[2] two fatty acid chains
[3] a phosphate group
[4] the alcohol
Cardiolipin is unique in that it has a “_____” phospholipid structure
double
True or False: In the cardiolipin structure, glycerol’s on either side and the middle, connecting the two portions of the molecules via the phosphate groups
True
Cardiolipin makes up ____% of the lipids of the inner mitochondrial membrane
a) 20%
b) 40%
c) 30%
d) 25%
a) 20%
Cardiolipin aids in relative _______ of the membrane, which allows a _______ gradient to be established -> essential for the electron transport chain and cellular respiration
impermeability; proton
What are Sphingolipids?
They are phospholipids built on a sphingosine platform called sphingolipids
Sphingolipids are ______ in the outer leaflet of plasma membrane
high
___________ is a common membrane sphingolipid and is common in myelin sheath of nerve cells
Sphingomyelin
True or False: Glycolipids = carbohydrate containing lipids
True
True or False: The carbohydrate component of a glycolipid will typically be in the intracellular surface of a cell membrane
False: The carbohydrate component of a glycolipid will typically be in the extracellular surface of a cell membrane
What are glycolipids derived from?
sphingosine
__________ are the simplest glycolipids with a single sugar residue, such as glucose or galactose
Cerebrosides
True or False: More complex glycolipids will include many more sugar moieties; typically, with seven sugar moieties
True
Steroids are built on a tetracyclic platform consisting of _______ cyclohexane rings and a ________ ring that are all used together –> this creates a __________
three; cyclopentane; steroid nucleus
Cholesterol is the most common _______ molecule and has an integral role in maintaining _________________
steroid; membrane integrity
True or False: Colesterol are important precursors for the assembly of steroid hormones
True
True or False: Unlike other molecules, Cholesterols like molecules are not important structural entities in prokaryotic cell membranes
False: Cholesterols like molecules (namely hopanoids) are important structural entities in prokaryotic cell membranes
True or False: Sterols play an important role in plants
True
Sometimes, the fatty acid component of the protein is referred to as the _______________, as it allows the protein to be _________ to the cell membrane
membrane anchor; anchored
