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Problem 23.1
Use Figure 23.1 to identify the family of lipids to which each of these molecules belongs.
b. <IMAGE>
Problem 23.14
Draw the structure of the sphingomyelin that contains a myristic acid acyl group. Identify the hydrophilic head group and the hydrophobic tails in this molecule.
Problem 23.16
Which of the following terms apply to the compound shown below? (Hint: Look at the functional groups and the bonds involved to begin analyzing the compound part by part in comparison to the lipids discussed in this chapter.) <IMAGE>
e. A lipid
Problem 23.19
As noted earlier (Section 22.3), he first step in glycolysis, which occurs within cells, is phosphorylation of glucose to glucose 6-phosphate. Why does this step prevent passive diffusion of glucose back out of the cell?
Problem 23.2
One of the constituents of the carnauba wax used in floor and furniture polish is an ester of a 32-carbon straight-chain alcohol with a C20:0 straight-chain carboxylic acid. Draw the structure of this ester. (Use subscripts to show the numbers of connected CH₂ groups.)
Problem 23.39
There are two isomeric triacylglycerol molecules whose components are glycerol, one palmitic acid unit, and two stearic acid units. Draw the structures of both, and explain how they differ.
Problem 23.5
Draw the complete structural formula of arachidonic acid (Table 23.1) in a way that shows the cis stereochemistry of its four double bonds.
Problem 23.5
Draw the structure of the product you would obtain on complete hydrogenation of the triacylglycerol in Problem 23.49. What is its name? Does it have a higher or lower melting temperature than the original triacylglycerol?
Problem 23.6
Show the structure of a cerebroside made up of d-galactose, sphingosine, and myristic acid.
Problem 23.6
Can there be any chiral carbon atoms in triacylglycerols? If so, which ones can be chiral and what determines their chirality?
Problem 23.72
Which process requires energy—passive or active transport? Why is energy sometimes required to move solute across the cell membrane?
Problem 23.74
Based on the information in Section 23.7, how would you expect each of these common metabolites to cross the cell membrane?
a. NO (nitrous oxide)
Problem 23.75
Based on the information in Section 23.7, how would you expect each of these common metabolites to cross the cell membrane?
a. CO
Problem 23.77
Identify the component parts of each saponifiable lipid listed in Problem 23.76.
Problem 2213
Identify the products formed by complete hydrolysis of all ester bonds in (a) the phosphatidylcholine on page 726.
Problem 2313
Identify the products formed by complete hydrolysis of all ester bonds in(b) the sphingomyelin in Figure 23.5.
Problem 2323
A membrane lipid was isolated and completely hydrolyzed. The following products were detected: ethanolamine, phosphate, glycerol, palmitic acid, and oleic acid. Propose a structure for this membrane lipid, and name the family (Table 23.3) to which it belongs.
Problem 2348
Is the reaction shown here esterification, hydrogenation, hydrolysis, saponification, or substitution? <IMAGE>
Problem 2349
Draw the structures of all products you would obtain by saponification of the following lipid with aqueous KOH. What are the names of the products? <IMAGE>
