chapter 10: lipids
Which of the following does not represent an appropriate head group for a membrane lipid? -inositol -choline -ethanolamine -serine -valine
valine
____ includes two fatty acids joined to glycerol by ester linkages (3)
Galactolipid, Glycerophospholipid, sulfolipid includes two fatty acids joined to ____ by ____ linkage
The building blocks for many lipids are _____, and they generally contain an even number of carbon atoms and an unbranched hydrocarbon chain.
fatty acids
What is the systematic name for the following fatty acid?
12:1(Δ5) trans-5-Dodecanoic acid
Which of the following structures is not an omega-3 (ω-3) polyunsaturated fatty acid (PUFA)? -18:3 (Δ9,12,15) -22:6 (Δ4,7,10,13,16,19) -20:4 (Δ5,8,11,13) -20:5 (Δ5,.8,11,14,17) -18:4 (Δ6,9,12,15)
20:4 (Δ5,8,11,13) https://en.wikipedia.org/wiki/Omega-3_fatty_acid
___ have hydrocarbons linked to glycerol by bonds that are more stable in acidic or high temperature environments (1)
Archaeal lipids have hydrocarbons linked to ___ by bonds that are ___ stable in acidic or high temperature environments
Olive oil, beef fat, and butter are natural fats that differ in their fatty acid composition. Based on the properties of these fats, rank them on their C16 and C18 saturated fatty acid levels.
Beef fat > Butter > Olive oil
Which of the following is an advantage of using polysaccharides over lipids as a source of energy?
Carbohydrates are a quick source of energy compared to lipids because they are water soluble.
In addition to hemolysis, phospholipase A2 envenomation causes inflammation and pain. What is one mechanism?
Phospholipase can release an eicosaniod present at C-2 in some lecithins
lysolecithin is found in the body naturally ...
Lysophospholipase removes the fatty acid at C-1
Select the molecules that contains sphingosine.
Molecule A, Molecule C, sphingomyelins https://www.chegg.com/homework-help/questions-and-answers/following-molecules-contain-sphingosine-select-apply-q3888337
_____ contains one fatty acid (1)
Sphingolipid contains ____ fatty acid
Three examples of steroids are shown. What basic ring structure is common to all steroids?
The steroid core structure is typically composed of 17 carbon atoms, bonded in 4 "fused" rings: -3 six-member cyclohexane rings AND -1 five-member cyclopentane ring https://www.chegg.com/homework-help/steroid-basic-ring-structure-common-steroids-sketch-example-chapter-21-problem-51qp-solution-9780538736404-exc
Triacylglycerols are not a structural component of membranes. Why are these molecules inappropriate for this function?
They do not contain a polar group and are therefore not amphipathic.
In which ways can dietary intake of trans fatty acids contribute to a higher incidence of cardiovascular disease?
They raise the levels of triacylglycerols and LDL cholesterol and lower HDL cholesterol levels.
example 3: A mixture of lipids is applied to a silica gel column, and the column is then washed with increasingly polar solvents. Arrange the lipids in order of elution by placing the first lipid to elute at the top.
cholesterol ester, diglyceride, sphingosine, sphingomyelin, phosphatidylglycerol
Describe the chemical steps, in order, that are involved in the conversion of β−carotene into retinoic acid.
cleavage, alcohol oxidation, aldehyde oxidation
Coenzyme Q (also called CoQ10 or ubiquinone) is a popular dietary supplement. In what type of reactions does coenzyme Q participate within a cell?
oxidation-reduction
When glycerol is esterified to two fatty acids and a phosphoric acid molecule a ___ is formed. These are found in biological membranes.
phosphoacylglycerol (glycerophosolipid)
The storage form of lipids a ___, accumulating in adipose tissue, and they can be used as metabolic fuel. These compounds have a polar part, made of three ester groups, and a nonpolar fatty acid tail.
triglycerol
Cholesterol is synthesized from a large linear precursor called squalene through a remarkable cyclization reaction involving epoxidation followed by rearrangement of electrons to produce the steroid nucleus. Squalene is assembled using individual isoprene groups. How many isoprene units are used in the construction of one molecule of cholesterol?
6
q1
a1
q2
a2
Arrange the fatty acids from highest melting point to lowest melting point.
https://www.chegg.com/homework-help/questions-and-answers/arrange-following-fatty-acids-highest-melting-point-lowest-melting-point-ch3-ch2-10cooh-ch-q23207075
A long‑chain amino alcohol joined, either by a glycosidic linkage or a phosphodiester linkage, to a fatty acid make up ___. These do not contain ___. They are abundant in the nervous system.
sphingolipid; glycerol
The top lipid is an example of a(n) ___, while the bottom lipid is an example of a(n) ___.
sphingolipid; glycerophospholipid
Which of the following lipids is the most polar?
yellow (bottom)
Catalytic hydrogenation, used in the food industry, converts double bonds in the fatty acids of vegetable oil triacylglycerols to −CH2−CH2−. Identify statements that correctly describe characteristics of catalytically hydrogenated food oils. -Catalytic hydrogenation oxidizes double bonds, decreasing melting temperature. -Catalytic hydrogenation reduces double bonds, increasing melting temperature. -Catalytic hydrogenation combats the oxidative cleavage that causes fats to become rancid. -Partially hydrogenated oils may cause health risks due to the presence of trans fats. -Hydrogenating oils reduce shelf life but create a good source of healthy fats.
-Catalytic hydrogenation reduces double bonds, increasing melting temperature. -Catalytic hydrogenation combats the oxidative cleavage that causes fats to become rancid. -Partially hydrogenated oils may cause health risks due to the presence of trans fats.
Classify the phrases based on whether they describe prostaglandins, leukotrienes, or both prostaglandins and leukotrienes. -Prostaglandins -Leukotrienes -Both
-Prostaglandins in synthetic form , used to induce labor/ child birth stimulate uterine contractions contain a ring structure with at least three or more carbons -Leukotrienes trigger asthmatic response -Both derived from arachidonic acid cause inflammation (Leukotrienes are synthesized in the cell from arachidonic acid by arachidonate 5-lipoxygenase also arachidonic acid is a intermediate in the production of Prostaglandin) (Through their role in vasodilation, prostacyclins are also involved in inflammation also leukotrienes are involved in causing inflammation)
Unsaturated fatty acids are often classified according to the number of carbon atoms between the terminal methyl carbon (the omega carbon) and the closest double bond to the methyl end of the chain. An omega‑3 fatty acid, for example, would have a double bond in position 3 counting from the methyl end of the molecule. Identify which omega class each fatty acid belongs to. palmitoleic acid oleic acid linoleic acid arachidonic acid a-linoleic acid y-linoleic acid eicosapentaenoic acid (EPA) which classes of fatty acids are considered essential fatty acids?
-omega 3 a-linoleic acid eicosapentaenoic acid (EPA) -omega 6 y-linoleic acid arachidonic acid linoleic acid -omega 7 palmitoleic acid -omega 9 oleic acid essential fatty acids: omega 3 & omega 6
Fatty acids are carboxylic acids with a long, unbranched hydrocarbon chain. There are three main classes of fatty acids. Classify the fatty acids as saturated, monounsaturated, or polyunsaturated. linoleic acid? oleic acid? palmitic acid? steric acid? arachidonic acid?
-saturated stearic acid palmitic acid -monounsaturated oleic acid -polyunsaturated arachidonic acid linoleic acid
Vitamins A, D, E, and K are fat‑soluble vitamins. Classify the phrases as describing vitamin A, vitamin D, vitamin E, or vitamin K. -vitamin A -vitamin D -vitamin E -vitamin K
-vitamin A hormone precursor & visual pigment regulates gene expression in epithelial tissue precursor of retinal causes dry skin deficiency -vitamin D production takes place in skin hormone precursor derived from steroid deficiency can cause rickets regulates calcium uptake by intestine production requires UV light -vitamin E prevents oxidative damage to membrane lipids antioxidant -vitamin K cofactor functions in clotting
Match the function or disease to the vitamin. -vitamin K -vitamin E -vitamin D -vitamin A
-vitamin K coagulation hemorrhagic disease -vitamin E reducing agent -vitamin D rickets calcium homeostasis -vitamin A vision cellular differentiation; vision birth defects; night blindness
Which of the following statements about the degradation of phospholipids and sphingolipids is incorrect? -Gangliosides are degraded by sets of lysosomal enzymes. -A lysophospholipid is produced when a phospholipase removes both fatty acids. -Tay-Sachs disease occurs when the body lacks hexosaminidase A, an enzyme that breaks down GM2. -Stepwise removal of sugar units in gangliosides will eventually yield a ceramide.
A lysophospholipid is produced when a phospholipase removes both fatty acids.
Select the statements about fatty acid melting points that are true. -A saturated fatty acid with a greater molar mass has a higher melting point than a saturated fatty acid with a lower molar mass. -A saturated fatty acid with a greater molar mass has a lower melting point than a saturated fatty acid with a lower molar mass. -A saturated fatty acid has a higher melting point than an unsaturated fatty acid. -A saturated fatty acid has a lower melting point than an unsaturated fatty acid.
A saturated fatty acid with a greater molar mass has a higher melting point than a saturated fatty acid with a lower molar mass. A saturated fatty acid has a higher melting point than an unsaturated fatty acid.
____ are common in plasma membrane (2)
Galactolipids and sulfolipids are common in ____
____ are made up of a 1,2-diacylglycerol and a polar head group alcohol attached by a phosphodiester bond (1)
Glycerophospholipids are made up of a 1,2-diacylglycerol and a polar head group ____ attached by a ____ bond
A mixture of lipids is applied to a silica gel column, and the column is then washed with increasingly polar solvents. Arrange the lipids in order of elution by placing the first lipid to elute at the top. -sphingosine -cholesterol ester -phosphatidylcholine -phosphatidylserine -diglyceride
Molecule which is non-polar will eluted first and one which is most polar will be eluted last. Thus, order will be: Cholesterol ether (eluted first) diglyceride sphingosine Phosphatidil choline Phosphatidil serine (eluted last)
____ do not contain the glycerol
Sphingolipids do not contain the ____
___ can contain phosphate (3)
Sphingolipids, glycerophospholipids, and archaeal lipids can contain ___
___ contains sulfates as functional group (1)
Sulfolipids contains ____ as functional group
The following molecule resembles a triacylglycerol, but is not. Why can this molecule not be classified as a triacylglycerol?
The chain on carbon 3 is not an ester linkage.
Which of the following generalizations about unsaturated fatty acids is incorrect? -Double bonds of polyunsaturated fatty acids are almost always separated by a methylene group. -Trans double bonds are found in nearly all naturally occurring unsaturated fatty acids. -In monounsaturated fatty acids, the double bond is generally between C-9 and C-10. -Double bonds of polyunsaturated fatty acids are almost never conjugated.
Trans double bonds are found in nearly all naturally occurring unsaturated fatty acids.
When vasopressin activates phospholipase C in the membrane, phosphatidylinositol 4,5−bisphosphate is hydrolyzed to release two products that are intracellular messengers. Which of the products remains associated with the plasma membrane?
diacylglycerol
The _________ attach to and activate carbohydrate units term-1during the synthesis of glycoproteins and glycolipids.
dolichols
When a carbohydrate is glycosidically linked to a hydroxyl group of a lipid, ___ are formed. Examples include gangliosides and cerebrosides. These are also found in biological membranes.
glycolipid
The venom of the Eastern diamondback rattler and the Indian cobra contains phospholipase A2, which catalyzes the hydrolysis of fatty acids at the C‑2 position of glycerophospholipids. The phospholipid breakdown product of this reaction is lysolecithin (lecithin is phosphatidylcholine). At high concentrations, lysophospholipids act as detergents, dissolving the membranes of erythrocytes and lysing the cells. Extensive hemolysis may be life‑threatening. Draw the lysolecithin that results when a phosphatidylcholine molecule is exposed to phospholipase A2. Use the groups tool to represent any acyl groups as R.R. Assume physiological pH.
https://www.chegg.com/homework-help/questions-and-answers/draw-lysolecithin-results-phosphatidylcholine-molecule-exposed-phospholipase-a2-represent--q41378414 https://www.chegg.com/homework-help/questions-and-answers/venom-eastern-diamondback-rattler-indian-cobra-contains-phospholipase-a2-catalyzes-hydroly-q24600491
Which of the designations are accurate for the fatty acid?
https://www.chegg.com/homework-help/questions-and-answers/following-designations-accurate-fatty-acid-shown-one-answer-q28565983
Glycerophospholipids (phosphoglycerides) are components of cell membranes. They are composed of a glycerol molecule with two fatty acids attached to the first and second carbon atoms, and a polar (hydrophilic) group attached through a phosphodiester linkage to the third carbon atom. Each of the given molecules is a glycerophospholipid. Fatty acid tails are represented by the symbols R1R1 and R2R2 . Match each structure with the correct name. There will be one structure for each name. -Phosphatidic acid (phosphatidate) -Phosphatidylinositol -Phosphatidylserine -Phosphatidylcholine
https://www.chegg.com/homework-help/questions-and-answers/glycerophospholipids-phosphoglycerides-components-cell-membranes-composed-ofa-glycerol-mol-q28214433
Phospholipids are components of cell membranes. One type of phospholipid, phosphatidylinositol (PI), is found in all tissues and cell types and is a precursor of second messengers in eukaryotes. The image shows phosphatidylinositol, with the inositol group represented by the letter X. Label the ring structure illustrated in the image so that it shows myo‑inositol, a molecule with the systematic name cis‑1,2,3,5‑trans‑4,6‑cyclohexanehexol. Carbon 1 of the ring is attached to the rest of the glycerophospholipid, which is represented by the letter R.
https://www.chegg.com/homework-help/questions-and-answers/phospholipids-components-cell-membranes-one-type-phospholipid-phosphatidylinositol-pi-foun-q41433302
Membrane glycerophospholipids have head group substituents that confer the lipids with a charge that can contribute to the surface properties of membranes. Rank the following glycerophospholipids from most negatively charged to most positively charged: phosphatidylcholine, phosphatidylinositol 4,5−bisphosphate, cardiolipin.
phosphatidylinositol 4,5−bisphosphate, cardiolipin, phosphatidylcholine
If a scientist were interested in cleaving the phosphodiester bonds in the head group of a glycerophospholipid like phosphatidylinositol 4,5−bisphosphate, which phospholipase would be a good choice?
phospholipase D & phospholipase C
Which of the following is an eicosanoid responsible for stimulating contraction of the smooth muscle of the uterus during labor?
prostaglandin
NSAIDS, nonsteroidal anti-inflammatory drugs, block the formation of ___ from arachidonate by inhibiting the enzyme cyclooxygenase.
prostaglandin & thromboxane
Compounds that contain a fused ring system are called ___. These are three 6-membered rings and one 5‑membered ring. Some of these compounds are found in biological&nnbsp; membranes.
steroids
example 2: A mixture of lipids is applied to a silica gel column, and the column is then washed with increasingly polar solvents. Arrange the lipids in order of elution by placing the first lipid to elute at the top.
triglyceride- having no charge is extremely non polar. hence gets eluted first cholesterol- same as triglyceride sphingosine- having one charged group sphingomyelin- having two charged group phosphatidyl serine- having a charged head
