Lipid Classifications - Biochemistry
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Which component of a phospholipid imparts a charge upon the macromolecule and therefore makes the head hydrophilic?
Which component of a phospholipid imparts a charge upon the macromolecule and therefore makes the head hydrophilic?
Phospholipids are amphipathic, meaning they have an end that is hydrophobic (the fatty acid tail) and an end that is hydrophilic (the head). Phosphate groups have a negative charge, thus attracting them to water, and the presence of a phosphate group at the head of a phospholipid makes that head hydrophilic. Glycerol itself polarizes a fatty acid, but the glycerol is located in the head, not the backbone, and is not charged like phosphate.
Phospholipids are amphipathic, meaning they have an end that is hydrophobic (the fatty acid tail) and an end that is hydrophilic (the head). Phosphate groups have a negative charge, thus attracting them to water, and the presence of a phosphate group at the head of a phospholipid makes that head hydrophilic. Glycerol itself polarizes a fatty acid, but the glycerol is located in the head, not the backbone, and is not charged like phosphate.
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In sufficient concentrations, one-tailed phospholipids will form a in solution.
In sufficient concentrations, one-tailed phospholipids will form a in solution.
The polar head groups and the hydrocarbon tails will separate themselves in such a way that one-tailed phospholipids will form micelles, whereas two-tailed phospholipids will form a bilayer (liposome).
The polar head groups and the hydrocarbon tails will separate themselves in such a way that one-tailed phospholipids will form micelles, whereas two-tailed phospholipids will form a bilayer (liposome).
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Which of the following is false about phospholipids?
Which of the following is false about phospholipids?
Phospholipids have two hydrocarbon tails, and one is indeed usually relatively saturated (has no double bonds) and the other relatively saturated (has double bonds). The degree of saturation, as well as the length, influences membrane fluidity; more cis-double bonds pack together less tightly, and decrease fluidity. In order to minimize free energy, the hydrophobic parts of phospholipids rearrange to refill a bilayer if it happens to break. In water, phospholipids can form a membrane, or a sphere called a micelle in which the hydrophobic tails pack together. Note that the tails are hydrophobic, and the heads are hydrophilic; tails are oriented toward the interior of a bilayered membrane.
Phospholipids have two hydrocarbon tails, and one is indeed usually relatively saturated (has no double bonds) and the other relatively saturated (has double bonds). The degree of saturation, as well as the length, influences membrane fluidity; more cis-double bonds pack together less tightly, and decrease fluidity. In order to minimize free energy, the hydrophobic parts of phospholipids rearrange to refill a bilayer if it happens to break. In water, phospholipids can form a membrane, or a sphere called a micelle in which the hydrophobic tails pack together. Note that the tails are hydrophobic, and the heads are hydrophilic; tails are oriented toward the interior of a bilayered membrane.
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Why do phospholipids and glycolipids form bilayers rather than micelles when placed in an aqueous media?
Why do phospholipids and glycolipids form bilayers rather than micelles when placed in an aqueous media?
Phospholipids and glycolipids have two hydrocarbon chains, whereas free fatty acids only have one. The extra carbon tail, in combination with the unsaturation of these types of lipids (double bonds present) makes them far bulkier than free fatty acids. The extra bulk disallows micelle formation, and bilayers (liposomes) form instead.
Phospholipids and glycolipids have two hydrocarbon chains, whereas free fatty acids only have one. The extra carbon tail, in combination with the unsaturation of these types of lipids (double bonds present) makes them far bulkier than free fatty acids. The extra bulk disallows micelle formation, and bilayers (liposomes) form instead.
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Which of the following is not a component of a typical phospholipid?
Which of the following is not a component of a typical phospholipid?
A typical phospholipid is made up of a glycerol with two fatty acid carbon chains stemming off of it. On the other side of the glycerol a phosphate group is connected, an ester group connects the tail to the head. An amino group, however, is not present.
A typical phospholipid is made up of a glycerol with two fatty acid carbon chains stemming off of it. On the other side of the glycerol a phosphate group is connected, an ester group connects the tail to the head. An amino group, however, is not present.
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Which component of a phospholipid imparts a charge upon the macromolecule and therefore makes the head hydrophilic?
Which component of a phospholipid imparts a charge upon the macromolecule and therefore makes the head hydrophilic?
Phospholipids are amphipathic, meaning they have an end that is hydrophobic (the fatty acid tail) and an end that is hydrophilic (the head). Phosphate groups have a negative charge, thus attracting them to water, and the presence of a phosphate group at the head of a phospholipid makes that head hydrophilic. Glycerol itself polarizes a fatty acid, but the glycerol is located in the head, not the backbone, and is not charged like phosphate.
Phospholipids are amphipathic, meaning they have an end that is hydrophobic (the fatty acid tail) and an end that is hydrophilic (the head). Phosphate groups have a negative charge, thus attracting them to water, and the presence of a phosphate group at the head of a phospholipid makes that head hydrophilic. Glycerol itself polarizes a fatty acid, but the glycerol is located in the head, not the backbone, and is not charged like phosphate.
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In sufficient concentrations, one-tailed phospholipids will form a in solution.
In sufficient concentrations, one-tailed phospholipids will form a in solution.
The polar head groups and the hydrocarbon tails will separate themselves in such a way that one-tailed phospholipids will form micelles, whereas two-tailed phospholipids will form a bilayer (liposome).
The polar head groups and the hydrocarbon tails will separate themselves in such a way that one-tailed phospholipids will form micelles, whereas two-tailed phospholipids will form a bilayer (liposome).
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Which of the following is false about phospholipids?
Which of the following is false about phospholipids?
Phospholipids have two hydrocarbon tails, and one is indeed usually relatively saturated (has no double bonds) and the other relatively saturated (has double bonds). The degree of saturation, as well as the length, influences membrane fluidity; more cis-double bonds pack together less tightly, and decrease fluidity. In order to minimize free energy, the hydrophobic parts of phospholipids rearrange to refill a bilayer if it happens to break. In water, phospholipids can form a membrane, or a sphere called a micelle in which the hydrophobic tails pack together. Note that the tails are hydrophobic, and the heads are hydrophilic; tails are oriented toward the interior of a bilayered membrane.
Phospholipids have two hydrocarbon tails, and one is indeed usually relatively saturated (has no double bonds) and the other relatively saturated (has double bonds). The degree of saturation, as well as the length, influences membrane fluidity; more cis-double bonds pack together less tightly, and decrease fluidity. In order to minimize free energy, the hydrophobic parts of phospholipids rearrange to refill a bilayer if it happens to break. In water, phospholipids can form a membrane, or a sphere called a micelle in which the hydrophobic tails pack together. Note that the tails are hydrophobic, and the heads are hydrophilic; tails are oriented toward the interior of a bilayered membrane.
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Why do phospholipids and glycolipids form bilayers rather than micelles when placed in an aqueous media?
Why do phospholipids and glycolipids form bilayers rather than micelles when placed in an aqueous media?
Phospholipids and glycolipids have two hydrocarbon chains, whereas free fatty acids only have one. The extra carbon tail, in combination with the unsaturation of these types of lipids (double bonds present) makes them far bulkier than free fatty acids. The extra bulk disallows micelle formation, and bilayers (liposomes) form instead.
Phospholipids and glycolipids have two hydrocarbon chains, whereas free fatty acids only have one. The extra carbon tail, in combination with the unsaturation of these types of lipids (double bonds present) makes them far bulkier than free fatty acids. The extra bulk disallows micelle formation, and bilayers (liposomes) form instead.
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Which of the following is not a component of a typical phospholipid?
Which of the following is not a component of a typical phospholipid?
A typical phospholipid is made up of a glycerol with two fatty acid carbon chains stemming off of it. On the other side of the glycerol a phosphate group is connected, an ester group connects the tail to the head. An amino group, however, is not present.
A typical phospholipid is made up of a glycerol with two fatty acid carbon chains stemming off of it. On the other side of the glycerol a phosphate group is connected, an ester group connects the tail to the head. An amino group, however, is not present.
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Lysosomal storage diseases occur when mutations cause defects in which of the following?
Lysosomal storage diseases occur when mutations cause defects in which of the following?
Lysosomal storage diseases occur when mutations cause defects in sphingolipid degradation enzymes. Simply put, the key word is "degradation," which indicates the presence of a disease. No other answer choice has a key word that indicates the presence of a disease.
Lysosomal storage diseases occur when mutations cause defects in sphingolipid degradation enzymes. Simply put, the key word is "degradation," which indicates the presence of a disease. No other answer choice has a key word that indicates the presence of a disease.
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Which of the following is the smallest sphingolipid in terms of molecular mass?
Which of the following is the smallest sphingolipid in terms of molecular mass?
All four of these sphingolipids differ only in the functional groups attached to the sphingosine. Ceramide has a fatty acid group; cerebroside has a monosaccharide group; ganglioside has a polysaccharide group; sphingomyelin has a phosphatidylcholine or phosphoethanolamine group. In terms of molecular mass, phosphatyidylcholine or phosphoethanolamine are the smallest as well as the least massive functional group, making sphingomyelin the sphingolipid with the smallest molecular mass.
All four of these sphingolipids differ only in the functional groups attached to the sphingosine. Ceramide has a fatty acid group; cerebroside has a monosaccharide group; ganglioside has a polysaccharide group; sphingomyelin has a phosphatidylcholine or phosphoethanolamine group. In terms of molecular mass, phosphatyidylcholine or phosphoethanolamine are the smallest as well as the least massive functional group, making sphingomyelin the sphingolipid with the smallest molecular mass.
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Which of the following is amphipathic, polar, and are formed by long-chain sphingolipids?
Which of the following is amphipathic, polar, and are formed by long-chain sphingolipids?
Glucosamine contributes to the structure of glycosylphosphatidylinositol (GPI). Ceramide is the precursor to sphingomyelin, sphingosine is hydrolyzed to form ceramide.
Glucosamine contributes to the structure of glycosylphosphatidylinositol (GPI). Ceramide is the precursor to sphingomyelin, sphingosine is hydrolyzed to form ceramide.
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Ceramide is a precursor to which of the following?
Ceramide is a precursor to which of the following?
Ceramide is formed by sphingosine. Sphingosine is formed by a long chain of sphingolipids. Both sphingomyelin and glycosphingolipids are formed from ceramide.
Ceramide is formed by sphingosine. Sphingosine is formed by a long chain of sphingolipids. Both sphingomyelin and glycosphingolipids are formed from ceramide.
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The myelin sheaths of neurons typically contain large quantities of .
The myelin sheaths of neurons typically contain large quantities of .
Myelin sheaths surround nerve cell axons and are essential for proper nervous system function. They act as an electrically insulating layer and enable better propagation of action potentials. Sphingomyelin is a type of sphingolipid found in the myelin sheaths of animal cell membranes.
Myelin sheaths surround nerve cell axons and are essential for proper nervous system function. They act as an electrically insulating layer and enable better propagation of action potentials. Sphingomyelin is a type of sphingolipid found in the myelin sheaths of animal cell membranes.
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Which of the following statements about oleic acid is false?
Which of the following statements about oleic acid is false?
Oleic acid (which composes much of olive oil) has a double bond between its 9th and 10th atoms. Hence it has an omega-9 unsaturation. It has 18 carbon atoms, not 16, which gives it a condensed molecular formula:
. Because it is a cis-isomer, the IUPAC name contains a Z, and becuse it is an unsaturated carboxylic acid, it ends in -enoic acid.
Oleic acid (which composes much of olive oil) has a double bond between its 9th and 10th atoms. Hence it has an omega-9 unsaturation. It has 18 carbon atoms, not 16, which gives it a condensed molecular formula:
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How many hydrogens are bound to a carbon atom in the middle of a saturated fatty acid chain?
How many hydrogens are bound to a carbon atom in the middle of a saturated fatty acid chain?
In a saturated fatty acid, all of the covalent carbon to carbon bonds are single bonds. So a carbon atom in the middle of the chain will have two covalent bonds to other carbon atoms, and can therefore bond to two hydrogen atoms.
In a saturated fatty acid, all of the covalent carbon to carbon bonds are single bonds. So a carbon atom in the middle of the chain will have two covalent bonds to other carbon atoms, and can therefore bond to two hydrogen atoms.
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Which of the following factors contribute to increasing the melting point of a fatty acid?
Which of the following factors contribute to increasing the melting point of a fatty acid?
Double bonds cause unsaturation, thus decreases the melting point. Cis-double bonds as well as methylation also introduce kinks within the chain, decreasing the melting point. Increasing the fatty acid chain length creates saturation, thus causes the melting point to increase. Therefore, decreasing fatty acid chain length has the adverse effect.
Double bonds cause unsaturation, thus decreases the melting point. Cis-double bonds as well as methylation also introduce kinks within the chain, decreasing the melting point. Increasing the fatty acid chain length creates saturation, thus causes the melting point to increase. Therefore, decreasing fatty acid chain length has the adverse effect.
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Select the most accurate description of alpha-linolenic acid.
Select the most accurate description of alpha-linolenic acid.
Alpha-linolenic acid is an essential fatty acid that must be consumed in the diet (cannot be synthesized by the body). It is an eighteen-carbon omega-3 fatty acid that is used to synthesize eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two important long chain polyunsaturated fatty acids. Alpha-linoleic acid is the precursor to arachodonic acid (AA).
Alpha-linolenic acid is an essential fatty acid that must be consumed in the diet (cannot be synthesized by the body). It is an eighteen-carbon omega-3 fatty acid that is used to synthesize eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two important long chain polyunsaturated fatty acids. Alpha-linoleic acid is the precursor to arachodonic acid (AA).
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Omega-6 fatty acids are primarily found in .
Omega-6 fatty acids are primarily found in .
Omega-6 fatty acids are primarily found in vegetable oils (ex. soybean oil or corn oil), chicken, and eggs. Note that poultry feed is very heavy on corn products and thus increases the omega-6 fatty acid proportion of almost all farm raised animals. Fish, chia seeds, and flax seeds are high in omega-3 fatty acids.
Omega-6 fatty acids are primarily found in vegetable oils (ex. soybean oil or corn oil), chicken, and eggs. Note that poultry feed is very heavy on corn products and thus increases the omega-6 fatty acid proportion of almost all farm raised animals. Fish, chia seeds, and flax seeds are high in omega-3 fatty acids.
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