Enter a player name to begin or load your saved progress.
The chemical formula for linoleic acid is C18H32O2.
Answer: True
Explanation: The chemical formula C18H32O2 accurately represents the molecular composition of linoleic acid, indicating 18 carbon atoms, 32 hydrogen atoms, and 2 oxygen atoms.
Linoleic acid has an acidity (pKa) value of approximately 4.77 at 25°C.
Answer: True
Explanation: The pKa of linoleic acid is reported as approximately 4.77 at 25°C, consistent with the acidic nature of its carboxylic acid functional group.
Linoleic acid is highly soluble in water due to its polar nature.
Answer: False
Explanation: Linoleic acid exhibits very low solubility in water (0.139 mg/L) due to its predominantly nonpolar, long hydrocarbon chain, despite the presence of a polar carboxylic acid group.
The molar mass of linoleic acid is approximately 280.452 grams per mole.
Answer: True
Explanation: The calculated molar mass for linoleic acid (C18H32O2) is approximately 280.452 g/mol.
Linoleic acid is identified by the IUPAC name (9Z,12Z)-Octadeca-9,12-dienoic acid.
Answer: True
Explanation: The systematic IUPAC name for linoleic acid, reflecting its structure with two cis double bonds at positions 9 and 12 on an 18-carbon chain, is (9Z,12Z)-Octadeca-9,12-dienoic acid.
The CAS Number for linoleic acid is 60-33-3.
Answer: True
Explanation: The Chemical Abstracts Service (CAS) Registry Number assigned to linoleic acid is indeed 60-33-3, serving as a unique identifier.
The SMILES string for linoleic acid represents it as a fully saturated fatty acid chain.
Answer: False
Explanation: The SMILES string for linoleic acid, CCCCC/C=C\C/C=C\CCCCCCCC(=O)O, explicitly denotes the presence of two double bonds, contradicting the representation of a fully saturated chain.
Linoleic acid is typically a solid at standard room temperature, with reported melting points above 20°C.
Answer: False
Explanation: Linoleic acid is a liquid at standard room temperature, with reported melting points significantly below 0°C, consistent with its classification as an unsaturated fatty acid.
Linoleic acid decomposes significantly before reaching its boiling point at atmospheric pressure.
Answer: True
Explanation: Like many long-chain fatty acids, linoleic acid tends to decompose upon heating to its theoretical atmospheric boiling point, necessitating boiling point measurements under reduced pressure.
What is the approximate flash point of linoleic acid?
Answer: 112°C (234°F)
Explanation: The flash point of linoleic acid is reported as 112°C (234°F), indicating the temperature at which it can produce sufficient vapor to ignite in the presence of an ignition source.
What does the common notation '18:2 (n-6)' for linoleic acid signify?
Answer: 18 carbons, 2 double bonds, second double bond at carbon 6 from the methyl end
Explanation: The notation '18:2 (n-6)' indicates that linoleic acid has an 18-carbon chain, two double bonds, and the first double bond is located at the sixth carbon atom counting from the methyl (omega) end of the fatty acid chain.
What is the reported solubility of linoleic acid in water?
Answer: Sparingly soluble, approximately 0.139 mg/L
Explanation: Linoleic acid exhibits very limited solubility in water, reported at approximately 0.139 mg/L, consistent with its hydrophobic hydrocarbon chain.
What is the density of linoleic acid as reported in the source?
Answer: 0.9 g/cm³
Explanation: The density of linoleic acid is reported as 0.9 g/cm³, indicating it is less dense than water.
What is the common notation for linoleic acid, indicating its carbon chain length and number of double bonds?
Answer: 18:2 (n-6)
Explanation: The common notation '18:2 (n-6)' for linoleic acid signifies an 18-carbon chain with two double bonds, the first of which is located at the sixth carbon from the omega end.
Linoleic acid's very low solubility in water is primarily due to:
Answer: Its long, nonpolar hydrocarbon chain.
Explanation: The extensive nonpolar hydrocarbon chain of linoleic acid dominates its molecular character, rendering it hydrophobic and thus poorly soluble in polar solvents like water.
Linoleic acid is classified as a saturated fatty acid due to its long hydrocarbon chain.
Answer: False
Explanation: The source identifies linoleic acid as a polyunsaturated omega-6 fatty acid, not a saturated one, due to the presence of two carbon-carbon double bonds.
Linoleic acid contains only one carbon-carbon double bond in its molecular structure.
Answer: False
Explanation: Linoleic acid is characterized by the presence of two carbon-carbon double bonds within its 18-carbon chain, classifying it as a polyunsaturated fatty acid.
Alpha-linolenic acid is an isomer of linoleic acid, differing only in the position of one double bond.
Answer: False
Explanation: Alpha-linolenic acid is an isomer of linoleic acid in terms of carbon chain length (18 carbons) and number of double bonds (three vs. two), but it is an omega-3 fatty acid, whereas linoleic acid is omega-6, indicating a difference in the position of the first double bond and the total number of double bonds.
What is the primary classification of linoleic acid based on its structure and double bonds?
Answer: Polyunsaturated omega-6 fatty acid
Explanation: Linoleic acid is classified as a polyunsaturated fatty acid due to its two carbon-carbon double bonds, and specifically as an omega-6 fatty acid because its first double bond is located at the sixth carbon atom from the methyl end.
Which of the following compounds is mentioned as being isomeric to linoleic acid?
Answer: Taxoleic acid
Explanation: Taxoleic acid is identified as an isomer of linoleic acid, sharing the same molecular formula but differing in the arrangement of its double bonds.
The cis configuration of the double bonds in linoleic acid is stated to be vital for:
Answer: Its chemical properties and biological functions.
Explanation: The cis configuration of linoleic acid's double bonds is crucial for its specific three-dimensional structure, which dictates its chemical reactivity and biological activity within metabolic pathways.
Which statement accurately describes the configuration of the double bonds in linoleic acid?
Answer: Both double bonds are in the cis configuration.
Explanation: Linoleic acid is characterized by two double bonds, both of which are in the cis configuration, contributing to its molecular shape and chemical properties.
Humans can synthesize linoleic acid internally, making dietary intake non-essential.
Answer: False
Explanation: Linoleic acid is an essential fatty acid for humans, meaning the body cannot synthesize it and must obtain it through dietary sources.
Linoleic acid serves as the primary precursor for the synthesis of arachidonic acid (AA) in the human body.
Answer: True
Explanation: Linoleic acid is the metabolic precursor from which arachidonic acid (AA) is synthesized in the human body through a series of enzymatic conversions.
The metabolic conversion of linoleic acid to arachidonic acid begins with the enzyme Δ6 desaturase.
Answer: True
Explanation: The enzymatic pathway converting linoleic acid to arachidonic acid initiates with the action of Δ6 desaturase, which transforms linoleic acid into gamma-linolenic acid (GLA).
Signaling molecules like prostaglandins are synthesized directly from linoleic acid without intermediate steps.
Answer: False
Explanation: Prostaglandins and other eicosanoids are synthesized from arachidonic acid (AA), which is itself synthesized from linoleic acid through multiple intermediate enzymatic steps.
Linoleoyl ethanolamide (LOE) has been identified as a natural inhibitor of the enzyme FAAH.
Answer: True
Explanation: Linoleoyl ethanolamide (LOE) is recognized as a naturally occurring inhibitor of Fatty Acid Amide Hydrolase (FAAH), an enzyme crucial in endocannabinoid degradation.
Why is linoleic acid considered an essential nutrient for humans?
Answer: Humans lack the metabolic pathways to synthesize it internally.
Explanation: Linoleic acid is classified as essential because human metabolic pathways cannot synthesize it; therefore, it must be acquired through dietary intake.
What is the primary physiological significance of linoleic acid in the human body?
Answer: It serves as the precursor for arachidonic acid (AA).
Explanation: Linoleic acid's primary physiological significance lies in its role as the essential precursor for the synthesis of arachidonic acid (AA), which is subsequently used to produce various signaling molecules.
Which of the following is NOT listed as a signaling molecule derived from arachidonic acid (which is derived from linoleic acid)?
Answer: Linoleic acid itself
Explanation: Prostaglandins, leukotrienes, and thromboxanes are all signaling molecules derived from arachidonic acid. Linoleic acid is a precursor to arachidonic acid, not a derivative of it.
Which enzyme initiates the metabolic pathway converting linoleic acid to arachidonic acid?
Answer: Δ6 desaturase
Explanation: The initial enzymatic step in the conversion of linoleic acid to arachidonic acid involves the enzyme Δ6 desaturase, which introduces a double bond to form gamma-linolenic acid (GLA).
What is the primary role of Linoleoyl ethanolamide (LOE) in relation to endocannabinoid metabolism?
Answer: It inhibits FAAH, the enzyme that degrades endocannabinoids.
Explanation: Linoleoyl ethanolamide (LOE) functions as a natural inhibitor of FAAH, the enzyme responsible for the breakdown of endocannabinoids such as anandamide, thereby influencing the endocannabinoid system.
Which type of molecule can be formed from linoleic acid via cytochrome P450 epoxygenases?
Answer: Vernolic acid
Explanation: Cytochrome P450 epoxygenases can metabolize linoleic acid to form epoxide products, such as vernolic acid.
Linoleic acid is utilized in paints and varnishes because its double bonds facilitate oxidation and film formation.
Answer: True
Explanation: The presence of double bonds in linoleic acid allows for autoxidation and crosslinking upon exposure to air, enabling the formation of durable films essential for paints and varnishes.
Linoleic acid's utility in varnishes is due to its ability to undergo autoxidation and crosslinking, forming a stable film, rather than hydrogenation.
Answer: True
Explanation: The drying and film-forming properties of oils rich in linoleic acid, used in varnishes, are primarily a result of autoxidation and crosslinking, not hydrogenation.
Topical application of linoleic acid in cosmetics is suggested to have anti-inflammatory effects and improve skin moisture.
Answer: True
Explanation: Research indicates that topical application of linoleic acid in cosmetic products may confer anti-inflammatory benefits and enhance skin barrier function, improving moisture retention.
Safflower oil and corn oil typically contain low concentrations of linoleic acid.
Answer: False
Explanation: Safflower oil and corn oil are notably rich in linoleic acid, often containing high concentrations, rather than low ones.
Salicornia oil is listed as having the highest reported linoleic acid content among the oils mentioned.
Answer: True
Explanation: According to the source data, Salicornia oil exhibits the highest reported concentration of linoleic acid, reaching up to 75%.
Olive oil contains a higher percentage of linoleic acid than soybean oil.
Answer: False
Explanation: Soybean oil typically contains a significantly higher percentage of linoleic acid (around 50.9%) compared to olive oil (around 8.4%).
When cockroaches die, they release linoleic acid to attract other cockroaches to the location.
Answer: False
Explanation: Cockroaches release oleic and linoleic acids upon death, but this acts as a deterrent, signaling other cockroaches to avoid the area, rather than attracting them.
Increased consumption of linoleic acid is associated with a higher risk of cardiovascular disease.
Answer: False
Explanation: Evidence suggests that increased consumption of linoleic acid is associated with a *reduced* risk of cardiovascular disease, partly due to its effect on lowering LDL cholesterol.
The American Heart Association recommends replacing saturated fats with linoleic acid in the diet.
Answer: True
Explanation: The American Heart Association advocates for the substitution of saturated fats with polyunsaturated fats, including linoleic acid, as a strategy to mitigate cardiovascular disease risk.
Which of the following vegetable oils is listed as having the highest reported concentration of linoleic acid?
Answer: Safflower oil (72-78%)
Explanation: Safflower oil is cited as containing one of the highest concentrations of linoleic acid among common vegetable oils, ranging from 72% to 78%.
What recommendation does the American Heart Association make regarding linoleic acid intake?
Answer: Replace saturated fats with linoleic acid to reduce cardiovascular risk.
Explanation: The American Heart Association recommends substituting saturated fats with linoleic acid as a dietary strategy to lower the risk of cardiovascular disease.
How does linoleic acid contribute to the drying properties of oil paints?
Answer: By undergoing autoxidation and crosslinking near its double bonds.
Explanation: The double bonds in linoleic acid are susceptible to autoxidation, leading to crosslinking reactions that polymerize the oil and form a hard, stable film, which is the basis for its use in drying oils for paints and varnishes.
In what form is linoleic acid most commonly found in nature?
Answer: As a triglyceride
Explanation: Linoleic acid typically occurs in natural sources, particularly in vegetable oils, esterified to glycerol as part of triglyceride molecules.
What unusual behavior related to linoleic acid is observed in cockroaches?
Answer: Its release upon death serves as a warning to deter other cockroaches.
Explanation: Upon death, cockroaches release oleic and linoleic acids, which function as a chemical signal to deter conspecifics from entering the vicinity, likely a survival mechanism.
Increased dietary intake of linoleic acid is strongly associated with which health benefit?
Answer: Lowered total blood cholesterol and LDL cholesterol.
Explanation: Research indicates that higher dietary intake of linoleic acid is correlated with reductions in total blood cholesterol and low-density lipoprotein (LDL) cholesterol levels, contributing to cardiovascular health.
Which of the following oils is NOT mentioned in the source as having a high concentration of linoleic acid?
Answer: Avocado oil
Explanation: While poppyseed oil, wheat germ oil, and corn oil are listed as having high concentrations of linoleic acid, avocado oil is not mentioned in this context.
According to clinical studies cited in the source, what is the effect of increased linoleic acid intake on inflammation markers?
Answer: It has a neutral effect, not negatively impacting inflammation markers.
Explanation: Clinical studies suggest that elevated linoleic acid intake does not adversely affect inflammation markers or oxidative stress levels.
The name 'linoleic acid' originates from the Latin word 'linum,' meaning 'flax,' and 'oleum,' meaning 'oil.'
Answer: True
Explanation: The nomenclature 'linoleic acid' is derived from the Latin terms 'linum' (flax) and 'oleum' (oil), reflecting its historical isolation from linseed oil.
Linoleic acid was first isolated by the chemist Justus von Liebig in 1844.
Answer: False
Explanation: While Justus von Liebig was a prominent chemist, the initial isolation of linoleic acid in 1844 is attributed to F. Sacc.
The determination of the two double bonds within the linoleic acid molecule was completed by K. Peters in 1886.
Answer: True
Explanation: K. Peters is credited with determining the presence of two double bonds in the linoleic acid molecule in 1886, a significant step in understanding its structure.
G. O. Burr and his colleagues were responsible for determining the chemical structure of linoleic acid in 1930.
Answer: False
Explanation: G. O. Burr and his colleagues discovered the essential role of linoleic acid in nutrition in 1930. The determination of its chemical structure was later achieved by T. P. Hilditch and his team.
The NFPA 704 health rating for linoleic acid is 0, indicating it poses no health hazard.
Answer: False
Explanation: The NFPA 704 health rating for linoleic acid is 2, signifying that intense or continued exposure may cause temporary incapacitation or residual injury, rather than posing no hazard.
Who is credited with discovering the essential role of linoleic acid in human nutrition?
Answer: G. O. Burr
Explanation: G. O. Burr and his colleagues are credited with the discovery of linoleic acid's essential role in human nutrition in 1930.
What does the NFPA 704 health rating of '2' for linoleic acid signify?
Answer: Intense or continued exposure may cause temporary incapacitation or residual injury.
Explanation: An NFPA 704 health rating of '2' indicates that exposure to linoleic acid could lead to temporary incapacitation or residual injury following intense or prolonged contact.
The name 'linoleic acid' is derived from Latin words meaning:
Answer: Flax and oil
Explanation: The term 'linoleic acid' originates from the Latin words 'linum' (flax) and 'oleum' (oil), referencing its initial isolation from linseed oil.
Linoleic acid was first isolated in 1844 from which specific source material?
Answer: Flax seeds (linseed oil)
Explanation: The initial isolation of linoleic acid in 1844 was performed using linseed oil, which is derived from flax seeds.
The determination of linoleic acid's chemical structure was achieved by which research group?
Answer: T. P. Hilditch's team
Explanation: The chemical structure of linoleic acid was determined by T. P. Hilditch and his research group.
What does the NFPA 704 flammability rating of '1' for linoleic acid imply?
Answer: It requires pre-heating before ignition can occur.
Explanation: A flammability rating of '1' on the NFPA 704 scale indicates that linoleic acid must be pre-heated before ignition can occur, suggesting it is not readily flammable at ambient temperatures.