BMSC 200 Module 8 Quiz – Lipids
Exam Questions and Answers
Triacylglycerols (triglycerides) - ANSWER-- Triacylglycerols are the storage lipids in
animals and plants.
- Three fatty acids linked to glycerol through ester linkages.
- Simple triacylglycerols have the same three fatty acids at each position, complex
triacylglycerols have different fatty acids.
- The ester linkage removes the polar carboxyl group to make a more hydrophobic
molecule.
Fats represent the key molecules for - ANSWER-long-term energy storage
On a gram per gram basis, there is six times as much energy in fats than
carbohydrates. - ANSWER-six times as much energy in fats than carbohydrates.
Low oxidation states - ANSWER-Less oxygenated fuels burn more efficiently;
triacylglycerols have lower oxygenation state than carbohydrates.
Low hydration states - ANSWER-lipids are hydrophobic with limited interaction with
water providing a more compact, dehydrated energy storage form.
Saponification - ANSWER-Treatment of fat with a strong base breaks the ester
linkages to release free fatty acids.
Fatty acids function as detergents and soaps through formation of - ANSWER-
micelles that capture hydrophobic molecules
Micelles - ANSWER-lipid molecules orient with polar (hydrophilic) head toward water
and nonpolar (hydrophobic) tails away from water (spherical)
Olestra - ANSWER-a synthetic fat made from sucrose and fatty acids that provides 0
kcalories per gram; also known as sucrose polyester.
- had dangerous side effects
Waxes - ANSWER-are non-polar esters of long-chain fatty acids and long chain
monohydroxylic alcohols.
• Waxes are very water insoluble and have high melting temps (60-100 C).
• They are widely distributed in nature as protective waterproof coatings on leaves,
fruits, animal skin, and feathers.
Formation of membranes is - ANSWER-a spontaneous consequence of the
properties of the molecules that compose them.
, The lipid components of membranes tend to have similar overall shapes and
properties - ANSWER-• Two hydrophobic tails and a hydrophilic head group.
Membrane lipids can be classified based on their - ANSWER-their backbone
(glycerol vs sphingosine) or by their polar head groups (phospho vs glyco).
Glycerophospholipids - ANSWER-- Most abundant lipids in membranes.
- Glycerol backbone with a phosphate at the C3 position (Glycerol 3-phosphate).
- Glycerol-3-Phosphate + 2 fatty acids = phosphatidate (or diacylglycerol 3-
phosphate)
- The phosphate group is the point of attachment for a variety of polar head groups.
Plant cells often contain - ANSWER-- galactolipids
- one or two galactose groups linked to C3 of diacylglycerol
- Plants also contain sulfolipids
Sphingolipids - ANSWER-- derived from sphingosine, a long chain amino alcohol
- structurally similar to monoacyl glycerol
- single fatty acid linked by amide bond to form ceramide
- Structurally, ceramide is similar to diacylglycerol.
Some common sphingolipids include: - ANSWER-a) sphingomyelins
- phosphocholine
b) Cerebrosides
- glycosphingolipid
- single sugar unit
c) Gangliosides
- glycosphingolipids
- multiple sugar units
Glycosphingolipids detemine - ANSWER-Blood type
- Cells are recognized as "self" vs "non- self" based on patterns of surface exposed
carbohydrates.
- Different blood types (A, B, O) reflect different sugar patterns as the head groups of
the sphingolipids.
The membrane lipids of extremophiles often contain: - ANSWER-- Ethers linkages
- Branch points within the hydrocarbon tails
- Membrane spanning hydrocarbon tails composed from a single molecule.
Steroids - ANSWER-- Sterols are structural membrane lipids.
- Sterols contain four fused ring steroid nucleus: 3-six carbon rings and a 5-carbon D
ring.
- Ring system is rigid and nearly planar.
Cholesterol - ANSWER-- mediates membrane fluidity
- also a precursor of steroid hormones and bile salts
Active roles for lipids include: - ANSWER-- Intracellular Signaling Molecules
- Hormones
Exam Questions and Answers
Triacylglycerols (triglycerides) - ANSWER-- Triacylglycerols are the storage lipids in
animals and plants.
- Three fatty acids linked to glycerol through ester linkages.
- Simple triacylglycerols have the same three fatty acids at each position, complex
triacylglycerols have different fatty acids.
- The ester linkage removes the polar carboxyl group to make a more hydrophobic
molecule.
Fats represent the key molecules for - ANSWER-long-term energy storage
On a gram per gram basis, there is six times as much energy in fats than
carbohydrates. - ANSWER-six times as much energy in fats than carbohydrates.
Low oxidation states - ANSWER-Less oxygenated fuels burn more efficiently;
triacylglycerols have lower oxygenation state than carbohydrates.
Low hydration states - ANSWER-lipids are hydrophobic with limited interaction with
water providing a more compact, dehydrated energy storage form.
Saponification - ANSWER-Treatment of fat with a strong base breaks the ester
linkages to release free fatty acids.
Fatty acids function as detergents and soaps through formation of - ANSWER-
micelles that capture hydrophobic molecules
Micelles - ANSWER-lipid molecules orient with polar (hydrophilic) head toward water
and nonpolar (hydrophobic) tails away from water (spherical)
Olestra - ANSWER-a synthetic fat made from sucrose and fatty acids that provides 0
kcalories per gram; also known as sucrose polyester.
- had dangerous side effects
Waxes - ANSWER-are non-polar esters of long-chain fatty acids and long chain
monohydroxylic alcohols.
• Waxes are very water insoluble and have high melting temps (60-100 C).
• They are widely distributed in nature as protective waterproof coatings on leaves,
fruits, animal skin, and feathers.
Formation of membranes is - ANSWER-a spontaneous consequence of the
properties of the molecules that compose them.
, The lipid components of membranes tend to have similar overall shapes and
properties - ANSWER-• Two hydrophobic tails and a hydrophilic head group.
Membrane lipids can be classified based on their - ANSWER-their backbone
(glycerol vs sphingosine) or by their polar head groups (phospho vs glyco).
Glycerophospholipids - ANSWER-- Most abundant lipids in membranes.
- Glycerol backbone with a phosphate at the C3 position (Glycerol 3-phosphate).
- Glycerol-3-Phosphate + 2 fatty acids = phosphatidate (or diacylglycerol 3-
phosphate)
- The phosphate group is the point of attachment for a variety of polar head groups.
Plant cells often contain - ANSWER-- galactolipids
- one or two galactose groups linked to C3 of diacylglycerol
- Plants also contain sulfolipids
Sphingolipids - ANSWER-- derived from sphingosine, a long chain amino alcohol
- structurally similar to monoacyl glycerol
- single fatty acid linked by amide bond to form ceramide
- Structurally, ceramide is similar to diacylglycerol.
Some common sphingolipids include: - ANSWER-a) sphingomyelins
- phosphocholine
b) Cerebrosides
- glycosphingolipid
- single sugar unit
c) Gangliosides
- glycosphingolipids
- multiple sugar units
Glycosphingolipids detemine - ANSWER-Blood type
- Cells are recognized as "self" vs "non- self" based on patterns of surface exposed
carbohydrates.
- Different blood types (A, B, O) reflect different sugar patterns as the head groups of
the sphingolipids.
The membrane lipids of extremophiles often contain: - ANSWER-- Ethers linkages
- Branch points within the hydrocarbon tails
- Membrane spanning hydrocarbon tails composed from a single molecule.
Steroids - ANSWER-- Sterols are structural membrane lipids.
- Sterols contain four fused ring steroid nucleus: 3-six carbon rings and a 5-carbon D
ring.
- Ring system is rigid and nearly planar.
Cholesterol - ANSWER-- mediates membrane fluidity
- also a precursor of steroid hormones and bile salts
Active roles for lipids include: - ANSWER-- Intracellular Signaling Molecules
- Hormones
