Chapter 11

A triacylglycerol consists of fatty acids attached to one glycerol. two glycerol phosphates. three cholesterols. one glycerol phosphate.

one glycerol.

The fatty acid oleate contains 18 carbons and a cis double bond after C‑9. Which designation describes the composition and structure of oleate? - 9:18 - 0:18 - 18:9 - 18:1

- 18:1

What is the difference between docosahexaenoate (DHA) and 19,20-dihydroxydocosapentaenoate (19,20-DHDP)? - DHA has a higher melting point than 19,20-DHDP. - Only DHA is a an 𝜔ω-3 fatty acid. - Only DHA is a polyunsaturated fatty acid. - 19,20-DHDP is more polar than DHA.

- 19,20-DHDP is more polar than DHA.

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.

Which statement does NOT describe a difference between archaeal membrane lipids and those of bacteria and eukaryotes? - Archaeal membrane lipids use ether linkages instead of ester linkages. - Archeal membrane lipids use a backbone other than glycerol. - Archaeal membrane lipids have long hydrophobic tails that are branched rather than linear. - Archaeal membrane lipids have long‑chain alcohol esters rather than fatty acid esters attached to the glycerol.

- Archeal membrane lipids use a backbone other than glycerol.

In phosphoglycerides, fatty acids are esterified at - a glycerol carbon and the phosphate group. - C‑1 and C‑2 of glycerol. - any two of the three glycerol carbons. - C‑1 and C‑3 of glycerol.

- C‑1 and C‑2 of glycerol.

Which of the statements are true? - Saturated fats are more likely than unsaturated fats to be solid at room temperature. - Saturated fats have lower melting points than unsaturated fats. - Triacylglycerols (triglycerides) always contain three identical fatty acids. - Triacylglycerols (triglycerides) are composed of fatty acid residues and glycerol. - Fats that contain more saturated fatty acid residues than unsaturated fatty acid residues are more likely to be solid at room temperature.

- Saturated fats are more likely than unsaturated fats to be solid at room temperature. - Triacylglycerols (triglycerides) are composed of fatty acid residues and glycerol. - Fats that contain more saturated fatty acid residues than unsaturated fatty acid residues are more likely to be solid at room temperature.

Which of the statements are true? - Yeast cells that produce more unsaturated fatty acids than saturated fatty acids in response to cold have greater cold tolerance. - Cell membranes in reindeer legs (near the hooves) are kept flexible because they have a large number of saturated fatty acids. - A plant that produces more monounsaturated fatty acids than polyunsaturated fatty acids in its membranes in winter has an increased resistance to freeze damage. - Cell membranes in cold tolerant winter wheat plants have a higher ratio of unsaturated fatty acids to saturated fatty acids than do cold intolerant wheat varieties.

- Yeast cells that produce more unsaturated fatty acids than saturated fatty acids in response to cold have greater cold tolerance. - Cell membranes in cold tolerant winter wheat plants have a higher ratio of unsaturated fatty acids to saturated fatty acids than do cold intolerant wheat varieties.

Unsaturated fatty acids have double bonds that are in the cis configuration. One of the consequences of this configuration is - an alteration in the charge of the molecule. - an alteration in the number of carbons in the molecule. - a bend in the molecule. - enhanced flexibility of the molecule.

- a bend in the molecule.

A glycolipid is: - a lipid molecule that contains a glycerol backbone and three fatty acids - a lipid molecule produced during glycolysis - a lipid molecule that contains at least one carbohydrate unit - a molecule produced in the reaction between a glycerol molecule and a lipid molecule

- a lipid molecule that contains at least one carbohydrate unit

Of the three major types of membrane lipids, which is NOT found in prokaryotes? - phospholipids - phosphoglycerides - glycolipids - cholesterol

- cholesterol

Which lipid or lipids must be obtained in the diet? - essential fatty acids - endogenous phospholipids - essential disaccharides - endogenous glycogen

- essential fatty acids

Select the molecules that can form the polar head group of phospholipids. - isoleucine - glycerol - serine - cyclopentanol

- glycerol - serine

Some lipid molecules are said to be amphipathic, meaning that they - are capable of moving rapidly from one side of a lipid bilayer to the other. - have asymmetric carbons and can exist in left- and right‑handed forms. - carry a positive charge on one end and a negative charge on the other end. - have a dual nature with part of the molecule being hydrophobic and the other part being hydrophilic.

- have a dual nature with part of the molecule being hydrophobic and the other part being hydrophilic.

Classify the characteristics of triacylglycerols and phosphoglycerides

Both triacylglycerols and phosphoglycerides have a glycerol backbone, but they differ in the number of fatty acid chains. Triacylglycerols have three fatty acid chains bound to the glycerol backbone, whereas phosphoglycerides have only two. In phosphoglycerides, the third carbon of the glycerol backbone is esterified to a phosphorylated alcohol instead of a fatty acid. Triacylglycerols are primarily used for storing fats used for fuel. Triacylglycerols are primarly found in adipose cells, also called fat cells, in adipose tissue. Triacylglycerols are a major source of energy. Migrating birds, such as the golden plover and ruby‑throated hummingbird, can fly long distances using triacylglycerols. Phosphoglycerides are an essential part of membranes. The phosphorylated alcohol group is polar and a necessary membrane component. The lipid bilayer forms when the polar glycerol heads associate with water and non‑polar tails form a hydrophobic barrier.

Which properties are true of this lipid? The lipid has two nonpolar tails. The lipid has a polar head group. The phosphate ester is hydrophobic. The hydrophobic chains are attracted to water due to hydrogen bonding. The lipid can form part of a cell membrane.

The lipid has two nonpolar tails. The lipid has a polar head group. The lipid can form part of a cell membrane.

In biological systems, fatty acids usually contain an even number of carbon atoms. Which fatty acids are MOST common in biological systems? fatty acids with 18 and 20 carbons fatty acids with 12 and 14 carbons fatty acids with 14 and 16 carbons fatty acids with 16 and 18 carbons

fatty acids with 16 and 18 carbons

Is the molecule shown hydrophilic, hydrophobic, or amphipathic (amphiphilic)?

hydrophobic

Select the molecules that contains sphingosine. phosphatidylcholine sphingomyelins Molecule A Molecule C Molecule B

sphingomyelins Molecule A Molecule C

Which of the designations are accurate for the fatty acid? 18:2(Δ6,918:2(Δ6,9) ω‑6 fatty acid 17:2(Δ8,11)17:2(Δ8,11) 8,11-octadecadienoic acid 18:2(Δ9,1218:2(Δ9,12)

ω‑6 fatty acid 18:2(Δ9,1218:2(Δ9,12)