Test Questions & Answers Ch17 Lipids and Their Functions in

General, Organic, and Biochemistry, 10e (Denniston)

Chapter 17 Lipids and Their Functions in Biochemical Systems

1) What is the common name for the fatty acid with the condensed structure shown below?

CH3(CH2)10COOH

A) lauric acid

B) oleic acid

C) capric acid

D) linoleic acid

E) arachidonic acid

2) Which statement concerning the structure of a fatty acid is FALSE?

A) Fatty acids are naturally occurring, long-chain carboxylic acids.

B) The carbon chain in a fatty acid may be branched or unbranched.

C) Fatty acids generally contain an even number of carbon atoms.

D) The carbon chain in a fatty acid may be saturated or unsaturated.

E) When present in fatty acids, C=C bonds are usually cis.

3) Which of the following is NOT classified as a type of eicosanoid?

A) steroids

B) prostaglandins

C) thromboxanes

D) leukotrienes

E) All are considered eicosanoids.

4) What response is caused by the prostaglandins produced in the kidneys?

A) stimulation of ovulation

B) smooth muscle contractions

C) dilation of renal blood vessels

D) constriction of blood vessels and aggregation of platelets

E) water retention and weight gain

5) Which eicosanoids produced by white blood cells can cause bronchial constriction?

A) prostaglandins

B) fatty acids

C) bile salts

D) leukotrienes

E) steroids

6) Which statement best describes how lipids are defined?

A) Lipids are biomolecules that contain the ester functional group.

B) Lipids are biomolecules that contain fatty acids.

C) Lipids are biomolecules that have negative effects on a person's health.

D) Lipids are biomolecules that are solids at room temperature.

E) Lipids are structurally diverse biomolecules that are soluble in nonpolar solvents and insoluble in water.

7) The structure of a phosphoglyceride is shown below. Phosphoglycerides can interact with both water and other lipids, and are therefore well suited for their role in the lipid bilayer of cell membranes. Which of the following best explains this behavior?

A) Phosphoglycerides contain a phosphate diester.

B) Phosphoglycerides contain both hydrophobic and hydrophilic regions.

C) Phosphoglycerides contain saturated fatty acids as well as unsaturated fatty acids.

D) Phosphoglycerides contain both single bonds and double bonds between carbons.

E) Phosphoglycerides contain omega-3 and omega-6 fatty acids.

8) Which of the following statements concerning lipid functions is NOT true?

A) The human body uses triglycerides for long-term energy storage, insulation, and protection.

B) Plants and animals use waxes as water barriers.

C) Phosphoglycerides are key components of the structure of cell membranes.

D) Steroids function as messenger molecules that enable cell-cell communication.

E) All statements concerning lipid functions are true.

9) What is the most abundant class of membrane lipids?

A) prostaglandins

B) triglycerides

C) waxes

D) phosphoglycerides

E) eicosanoids

10) What nitrogen-containing alcohol forms the backbone of the sphingolipids?

A) ethanolamine

B) ammonia

C) aniline

D) cortisol

E) sphingosine

11) Consider the compound represented below. Which of the following best describes it?

A) It is a nonpolar amino acid.

B) It is a triglyceride.

C) It is a soap.

D) It is an unsaturated fatty acid.

E) It is an omega-3 wax.

12) Cetyl palmitate is a component of spermaceti wax, isolated from the heads of sperm whales, and used in cosmetics. In which solvent would cetyl palmitate be expected to have the greatest solubility?

A) acetic acid (CH3COOH)

B) ethyl alcohol (CH3CH2OH)

C) decane (CH3(CH2)6CH3)

D) water

E) 5% NaCl(aq)

13) The ingredients on a box of cupcakes lists partially hydrogenated soybean oil. Partial hydrogenation of soybean oil has what effect?

A) It produces fatty acid salts from the triglycerides that are present.

B) It decreases the percentage of unsaturation present in the fatty acid side chains.

C) It hydrolyzes the triglycerides that are present.

D) It increases the number of fatty acids present.

E) It converts the soybean oil to butter.

14) What two products are formed in the hydrolysis of a wax?

A) a long-chain alcohol and an ester

B) a fatty acid and an ester

C) a fatty acid and a long-chain alcohol

D) a triglyceride and a soap

E) an alcohol and a bile salt

15) Which class of human plasma lipoproteins carries triglycerides from the intestine to other tissues?

A) chylomicrons

B) high density lipoproteins (HDL)

C) low density lipoproteins (LDL)

D) very low density lipoproteins (VLDL)

E) sphingomyelins

16) Which class of human plasma lipoproteins binds triglycerides synthesized in the liver and carries them to adipose for storage?

A) chylomicrons

B) high density lipoproteins (HDL)

C) low density lipoproteins (LDL)

D) very low density lipoproteins (VLDL)

E) sphingomyelins

17) Which class of lipoprotein carries cholesterol to peripheral tissues and helps regulate cholesterol levels in those tissues?

A) chylomicrons

B) high density lipoproteins (HDL)

C) low density lipoproteins (LDL)

D) very low density lipoproteins (VLDL)

E) sphingomyelins

18) Which class of lipoprotein is bound to plasma cholesterol and transports it from the peripheral tissues to the liver?

A) chylomicrons

B) high density lipoproteins (HDL)

C) low density lipoproteins (LDL)

D) very low density lipoproteins (VLDL)

E) sphingomyelins

19) How can the structure and composition of biological membranes be best described?

A) lipid bilayer

B) protein micelle

C) hydrophilic barrier

D) emulsifying layer

E) saturated triglyceride

20) Testosterone, cholesterol, and progesterone are all classified as steroids because they contain the steroid nucleus. Which of the following compounds would also be classified as a steroid?

A) I only

B) II only

C) III only

D) I and II

E) I, II, and III

21) How does the proportion of saturation and unsaturation in membrane lipids affect the fluidity of the cell membrane?

A) Membrane fluidity increases with an increase in the percentage of unsaturation.

B) Membrane fluidity decreases with an increase in the percentage of unsaturation.

C) Membrane fluidity increases with an increase in the percentage of saturation.

D) Membranes are most fluid when there is an equal proportion of saturation and unsaturation.

E) Membrane fluidity depends only on the size of the carbon chains, and not on the proportions of saturation and unsaturation.

22) A tube of lipstick lists capric triglyceride among its ingredients. Capric triglyceride is a simple triglyceride containing capric acid, a 10-carbon saturated fatty acid. What is the structure of capric triglyceride?

A)

B)

C)

D)

E)

23) Dietary fats and oils are structurally both triglycerides, but fats are solids and oils are liquids at room temperature. Which of the following best describes the reason for their difference in physical state?

A) Fats contain 3 identical fatty acid R groups and oils contain different R groups.

B) Oils contain 3 identical fatty acid R groups and fats contain different R groups.

C) Oils contain longer fatty acid R groups than fats do.

D) Fats contain more hydroxyl groups in their fatty acid R groups than oils do.

E) Oils contain a higher percentage of unsaturation in their fatty acid R groups than fats do.

24) When three fatty acids react with glycerol, a lipid known as a triglyceride is formed. How are the fatty acids bonded to glycerol?

A) by amide bonds

B) by ester bonds

C) by glycosidic linkages

D) by acetal bonds

E) by hydrogen bonding

25) When palmitic acid, a 16-carbon saturated fatty acid, reacts with a 30-carbon unbranched alcohol, a wax is formed. What is the structure of this wax?

A)

B)

C)

D)

E)

26) What two products are formed in the reaction between a fatty acid and an alcohol?

A) ester and hydrogen

B) ester and water

C) ether and water

D) ether and hydrogen

E) hydrogen and alkane

27) What is the name of the product that results from the hydrogenation reaction below?

A) stearic acid

B) arachidic acid

C) palmitic acid

D) linoleic acid

E) capric acid

28) What two fatty acids are essential fatty acids?

A) palmitoleic acid and oleic acid

B) linoleic acid and stearic acid

C) arachidonic acid and eicosanoids

D) linolenic acid and linoleic acid

E) stearic acid and oleic acid

29) What products are formed from the complete hydrolysis of a triglyceride?

A) glycerol and 3 fatty acids

B) glycerol and 2 fatty acids

C) glycerol and 1 fatty acid

D) All of the choices are correct.

E) None of the choices are correct.

30) Which lipid is found in egg yolks and soybeans and is used as an emulsifying agent in ice cream?

A) sphingosine

B) linoleic acid

C) lecithin

D) lauric acid

E) Both lecithin and lauric acid are correct.

31) What is the starting material for the synthesis of steroids in the body?

A) glucose

B) testosterone

C) stearic acid

D) cholate

E) cholesterol

32) Saponification of the triglyceride shown below produces soap. What is the structure of the soap?

A) Na+ −O(CH2)10CH3

B)

C)

D)

E)

33) What type of lipid is formed in the reaction between a long-chain alcohol and a fatty acid?

A) triglyceride

B) oil

C) steroid

D) cholesterol

E) wax

34) Glycolipids contain what type of compound joined to the lipid portion of the molecule?

A) protein

B) enzyme

C) vitamin

D) carbohydrate

E) amino acid

35) Fatty acids generally contain how many carbon atoms?

A) 12

B) 8

C) 6

D) an odd number

E) an even number

36) What type of fatty acid is represented by the formula CnH2nCOOH?

A) saturated fatty acid

B) unsaturated fatty acid

C) essential fatty acid

D) nonessential fatty acid

E) chiral fatty acid

37) What process converts an unsaturated fatty acid into a saturated fatty acid?

A) oxidation

B) combustion

C) substitution

D) hydrolysis

E) hydrogenation

38) What is the product of the complete hydrogenation of linoleic acid?

A) sodium linoleate

B) a diol

C) arachidonic acid

D) an ester

E) stearic acid

39) What highly unsaturated fatty acid and precursor to many prostaglandins, is synthesized from the fatty acid linoleic acid in the body?

A) oleic acid

B) linolenic acid

C) stearic acid

D) arachidonic acid

E) palmitoleic acid

40) Which of the following hormone-like molecules is NOT produced from arachidonic acid?

A) prostaglandins

B) eicosanoids

C) leukotrienes

D) thromboxanes

E) steroids

41) Which kind of eicosanoids is thought to promote certain aspects of the inflammatory response?

A) leukotrienes

B) prostaglandins

C) thromboxanes

D) steroids

E) fatty acids

42) Painful menstruation may be the result of an excess of which of the following eicosanoids?

A) leukotrienes

B) thromboxanes

C) prostaglandins

D) steroids

E) phospholipids

43) Cyclooxygenase catalyzes the conversion of arachidonic acid into PGH2. What drug inhibits this enzyme?

A) lactaid

B) aspirin

C) progesterone

D) norlutin

E) cortisone

44) What is the major energy storage form found in fat cells?

A) waxes

B) phospholipids

C) acetylcholines

D) triglycerides

E) low density lipids

45) What is the product that results upon complete hydrogenation of the fatty acid shown?

A)

B)

C)

D)

E)

46) What is another name for phosphatidylcholine?

A) phospholipid-D

B) sphingosine

C) cholinesterase

D) lecithin

E) chylomicron

47) Which lipid hormones allow tissues of the body to communicate with one another?

A) steroids

B) lipoproteins

C) enzymes

D) arachidonates

E) prostaglandins

48) Which steroid is responsible for both the successful initiation and completion of pregnancy?

A) cholesterol

B) sphingosine

C) chylomicron

D) progesterone

E) cortisone

49) What is the general term for lipids synthesized from isoprene units?

A) cholesterol

B) waxes

C) chylomicrons

D) terpenes

E) high density lipoproteins

50) Which of the following substances are not found in lipoproteins?

A) phospholipids

B) cholesterol

C) starch

D) proteins

E) triglycerides

51) High levels of one class of human plasma lipoprotein are thought to reduce the incidence of atherosclerosis. Which class is this?

A) chylomicrons

B) VLDL

C) LDL

D) HDL

E) cholinesterases

52) Which of the following fatty acids would be classified as an omega-6 fatty acid?

A) I

B) II

C) III

D) I and III

E) II and III

53) Sphingomyelins are a type of sphingolipid, cell membrane lipids that contain sphingosine, an 18-carbon amino alcohol, as the backbone of the structure. What type of bond joins the fatty acid portion of the sphingomyelin molecule to the sphingosine backbone?

A) C=C bond

B) amide bond

C) ionic bond

D) phosphodiester bond

E) hydrogen bond

54) Which of the following substances do not contribute to the structure of biological membranes?

A) phospholipids

B) glycolipids

C) cholesterol

D) proteins

E) cellulose

55) Which steroid is used in the treatment of rheumatoid arthritis, asthma, and many skin conditions?

A) testosterone

B) cortisone

C) digitoxin

D) cholesterol

E) stanozolol

56) How does the melting point of an unsaturated fatty acid compare to that of a saturated fatty acid with an equal number of carbon atoms?

A) The melting point of the unsaturated fatty acid will be higher than that of the saturated fatty acid.

B) The melting point of the unsaturated fatty acid will be lower than that of the saturated fatty acid.

C) The melting point of the unsaturated fatty acid will be the same as that of the saturated fatty acid.

D) It is impossible to predict without additional information.

E) Fatty acids do not have melting points because they are liquids at room temperature.

57) Which of the following is NOT a lipid?

A) fatty acids

B) glycerides

C) waxes

D) lipoproteins

E) All of the choices are correct.

58) Which statement concerning lipids is FALSE?

A) Lipids are used as an energy source.

B) Most of the energy stored in the body is in the form of lipids.

C) Glycogen is the lipid used for storing energy.

D) Lipids are stored in fat cells called adipocytes.

E) Lipids release more than twice the energy of carbohydrates when oxidized.

59) Which of the statements concerning the lipid bilayer of cell membranes is INCORRECT?

A) The lipid bilayer consists of two identical layers of phospholipids.

B) The hydrophobic hydrocarbon tails are located in the interior of the bilayer.

C) The ionic head groups of lipids are exposed on the exterior surface of the bilayer.

D) The hydrocarbon tails provide a thin shell of nonpolar material that prevents mixing of molecules on both sides of the bilayer.

E) Carbohydrate groups attached to the outer surface of the lipid bilayer participate in receptor and recognition functions.

60) Which of the following best describes the composition of the carbon chain in a saturated fatty acid?

A) contains cis- and trans- C=C (double) bonds

B) contains only C−C (single) bonds

C) contains at least one C−C (double) bond

D) contains only C=C (double) bonds

E) contains alternating C−C (single) and C=C (double) bonds

61) Which of the following leads to an increase in the melting point of a fatty acid?

A) increase in the length of the carbon chain

B) increase in the amount of unsaturation

C) decrease in the number of hydrogen atoms per carbon atom

D) All of the choices are correct.

E) None of the choices are correct.

62) What is the IUPAC name of the carboxylic acid formed by the hydrogenation of oleic acid (cis-9-octadecenoic acid)?

A) trans-9-octadecenoic acid

B) octadecanoic acid

C) octadecenoic acid

D) 9-octadecenoic acid

E) octadecanol

63) Which of the following is the reverse of an esterification reaction?

A) reduction of an ester

B) oxidation of an ester

C) neutralization of an ester

D) hydrolysis of an ester

E) hydrogenation of an ester

64) Which type of lipid always contains the carbon skeleton structure shown?

A) lipoproteins

B) glycerides

C) phospholipids

D) sphingolipids

E) steroids

65) All lipid molecules are characterized by having a polar "head" and a nonpolar "tail."

66) Unsaturated fatty acids contain only single bonds in their hydrocarbon chains.

67) One mole of oleic acid will react with two moles of hydrogen to form a mole of stearic acid.

68) The two essential fatty acids are oleic and linoleic acid.

69) Prostaglandins produced in the kidneys cause renal blood vessels to dilate.

70) Phospholipids have a polar "head" and a nonpolar "tail."

71) The most abundant lipids found in membranes are the phosphoglycerides.

72) The melting point of saturated fatty acids decreases with increasing number of carbons.

73) The product of the reaction of decanoic acid with n-propanol under acidic conditions is isopropyl decanoate.

74) A strong correlation exists between heart disease and the concentration of cholesterol found in blood plasma.

75) Bile salts are classified as steroids.

76) Fatty acids react with long chain alcohols to produce waxes.

77) Organisms that live at high temperatures tend to have higher proportions of unsaturated fatty acids in their cell membranes.

78) The cell membrane controls the flow of metabolites into and out of a cell.