Biochemistry Exam 4 – Lipids Explained: Fatty
Acids, Triacylglycerols & Membranes|Verified
Questions Provided with A+ Graded Rationales
Latest Updated 2026
What is the structure of fatty acids
nonpolar, hydrophobic tail and a polar, hydrophillic head
What are the two types of fatty acids
saturated and unsaturated
What is a unsaturated fat?
they are liquid a room temperature and they contain cis bonds.
What is a saturated fat?
They are all single bonds and are solid at room temperature
Why do saturated fat solidify at room temp and unsaturated fats liquify.
Saturated fats solidify because they lack double bonds are able to pack together. Unsaturated
fats contain double bonds cannot pack together, so they stay in a liquid state
What are all fatty acids built from?
Acetyl CoA
True or False: Fatty acids contain odd number of carbons
False, they contain even numbers of carbons
What does the "Z" stand for in the fatty acid notation?
Cis
What is the shorthand notation of a fatty acid
Total # of carbons: # double bonds, D double bond positions
Position of double bonds indicated by Dn, where n indicates what?
lower numbered carbon of each pair
,Fatty acids are important what?
metabolic fuels
Fatty acids produce how much more energy then proteins or carbohydrates?
2-3 time more
Fatty acids are stored as neutral lipids called
triacylglycerols
Triacylglycerols are very _________ and are stored in cells in a(n)____________ form
hydrophobic; anhydrous
What does anhydrous mean?
a substance containing no water
True or false: lipids are more efficient way to store energy
true
What is the structure of a triacylglycerol
Three fatty acids esterified to a glycerol backbone
What is the most abundant lipid in the membrane?
phosphoacylglycerols
What are the types of phosphoacylglycerols?
phospho:
-ethanolamine
-serines
-cholines
-inositols
what is the most common phosphoacylglycerol
phosphatidylcholine
What is the structure of phosphoacylglycerols
glycerol based lipids in which two hydroxyl groups are esterified to fatty acids and the third is
linked to a phosphate group attached to a polar alcohol.
What is a sphingosine
, a long-chain amino alcohol that serves as the backbone of sphingolipids, important structural
and signaling molecules in cell membranes.
What is the structure of a sphingosine
A long chain with an NH3+ group at one position and an alcohol (-OH) at another position
-Addition of a fatty acid at NH3+ = Ceramide
-Addition of a carbohydrate at (-OH) = glycosphingolipid
What is a sphingolipid?
contain sphingosine, a fatty acid, phosphate group, and small amino acid with polar and
nonpolar regions
What is sphingomyelin?
a phospholipid and a sphingolipid
What is the structure of sphingomyelin?
a sphingosine backbone, a fatty acid forming ceramide, and a phosphocholine head group
What is a cerebroside glycolipid?
a glycolipid consisting of a ceramide with one sugar residue (glucose or galactose)
what is the Ganglioside structure?
Oligosaccharide head group attached to the OH of sphingosine and a fatty acid tail attached to
the NH
What lipids do not contain esters of fatty acid
Steroids, eicosanoids (prostaglandins, thromboxanes, leukotrienes)
What is the structure of steroids?
four fused carbon rings
What is the function of cholesterol?
modulates the fluidity of mammalian cell membranes
What is the precursor of the steroid hormones and bile salts
cholesterols
True or false: the fused ring system makes cholesterol less flexible than most other lipids
true
Acids, Triacylglycerols & Membranes|Verified
Questions Provided with A+ Graded Rationales
Latest Updated 2026
What is the structure of fatty acids
nonpolar, hydrophobic tail and a polar, hydrophillic head
What are the two types of fatty acids
saturated and unsaturated
What is a unsaturated fat?
they are liquid a room temperature and they contain cis bonds.
What is a saturated fat?
They are all single bonds and are solid at room temperature
Why do saturated fat solidify at room temp and unsaturated fats liquify.
Saturated fats solidify because they lack double bonds are able to pack together. Unsaturated
fats contain double bonds cannot pack together, so they stay in a liquid state
What are all fatty acids built from?
Acetyl CoA
True or False: Fatty acids contain odd number of carbons
False, they contain even numbers of carbons
What does the "Z" stand for in the fatty acid notation?
Cis
What is the shorthand notation of a fatty acid
Total # of carbons: # double bonds, D double bond positions
Position of double bonds indicated by Dn, where n indicates what?
lower numbered carbon of each pair
,Fatty acids are important what?
metabolic fuels
Fatty acids produce how much more energy then proteins or carbohydrates?
2-3 time more
Fatty acids are stored as neutral lipids called
triacylglycerols
Triacylglycerols are very _________ and are stored in cells in a(n)____________ form
hydrophobic; anhydrous
What does anhydrous mean?
a substance containing no water
True or false: lipids are more efficient way to store energy
true
What is the structure of a triacylglycerol
Three fatty acids esterified to a glycerol backbone
What is the most abundant lipid in the membrane?
phosphoacylglycerols
What are the types of phosphoacylglycerols?
phospho:
-ethanolamine
-serines
-cholines
-inositols
what is the most common phosphoacylglycerol
phosphatidylcholine
What is the structure of phosphoacylglycerols
glycerol based lipids in which two hydroxyl groups are esterified to fatty acids and the third is
linked to a phosphate group attached to a polar alcohol.
What is a sphingosine
, a long-chain amino alcohol that serves as the backbone of sphingolipids, important structural
and signaling molecules in cell membranes.
What is the structure of a sphingosine
A long chain with an NH3+ group at one position and an alcohol (-OH) at another position
-Addition of a fatty acid at NH3+ = Ceramide
-Addition of a carbohydrate at (-OH) = glycosphingolipid
What is a sphingolipid?
contain sphingosine, a fatty acid, phosphate group, and small amino acid with polar and
nonpolar regions
What is sphingomyelin?
a phospholipid and a sphingolipid
What is the structure of sphingomyelin?
a sphingosine backbone, a fatty acid forming ceramide, and a phosphocholine head group
What is a cerebroside glycolipid?
a glycolipid consisting of a ceramide with one sugar residue (glucose or galactose)
what is the Ganglioside structure?
Oligosaccharide head group attached to the OH of sphingosine and a fatty acid tail attached to
the NH
What lipids do not contain esters of fatty acid
Steroids, eicosanoids (prostaglandins, thromboxanes, leukotrienes)
What is the structure of steroids?
four fused carbon rings
What is the function of cholesterol?
modulates the fluidity of mammalian cell membranes
What is the precursor of the steroid hormones and bile salts
cholesterols
True or false: the fused ring system makes cholesterol less flexible than most other lipids
true
