Deck 17: Lipids and Their Functions in Biochemical Systems

Question 1

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

Answer 1

I only

Question 2

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.

Answer 2

Phosphoglycerides contain both hydrophobic and hydrophilic regions.

Question 3

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

Answer 3

lipid bilayer

Question 4

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

Question 5

What is the most abundant class of membrane lipids?

A)prostaglandins
B)triglycerides
C)waxes
D)phosphoglycerides
E)eicosanoids

Question 6

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

Question 7

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

Question 8

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.

Question 9

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

A)prostaglandins
B)fatty acids
C)bile salts
D)leukotrienes
E)steroids

Question 10

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

Question 11

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

Question 12

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.

Question 13

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

A)ethanolamine
B)ammonia
C)aniline
D)cortisol
E)sphingosine

Question 14

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.

Question 15

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

Question 16

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.

Question 17

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

Question 18

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.

Question 19

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)

Question 20

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.

Question 21

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

A)Na^{+ −}O(CH₂)₁₀CH₃
B)

C)

D)

E)

Question 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)

Question 23

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

Question 24

Fatty acids generally contain how many carbon atoms?

A)12
B)8
C)6
D)an odd number
E)an even number

Question 25

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

Question 26

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

Question 27

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.

Question 28

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.

Question 29

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

Question 30

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

Question 31

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

Question 32

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.

Question 33

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)

Question 34

What type of fatty acid is represented by the formula C_nH_2nCOOH?

A)saturated fatty acid
B)unsaturated fatty acid
C)essential fatty acid
D)nonessential fatty acid
E)chiral fatty acid

Question 35

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.

Question 36

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

A)oxidation
B)combustion
C)substitution
D)hydrolysis
E)hydrogenation

Question 37

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

Question 38

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

Question 39

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

A)prostaglandins
B)eicosanoids
C)leukotrienes
D)thromboxanes
E)steroids

Question 40

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

A)glucose
B)testosterone
C)stearic acid
D)cholate
E)cholesterol

Question 41

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

Question 42

What is another name for phosphatidylcholine?

A)phospholipid-D
B)sphingosine
C)cholinesterase
D)lecithin
E)chylomicron

Question 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

Question 44

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

A)steroids
B)lipoproteins
C)enzymes
D)arachidonates
E)prostaglandins

Question 45

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

A)phospholipids
B)glycolipids
C)cholesterol
D)proteins
E)cellulose

Question 46

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.

Question 47

Which of the following substances are not found in lipoproteins?

A)phospholipids
B)cholesterol
C)starch
D)proteins
E)triglycerides

Question 48

Which of the following is NOT a lipid?

A)fatty acids
B)glycerides
C)waxes
D)lipoproteins
E)All of the choices are correct.

Question 49

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

Question 50

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.

Question 51

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

Question 52

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

Question 53

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

A)waxes
B)phospholipids
C)acetylcholines
D)triglycerides
E)low density lipids

Question 54

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

Question 55

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

A)cholesterol
B)waxes
C)chylomicrons
D)terpenes
E)high density lipoproteins

Question 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.

Question 57

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

Question 58

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

Question 59

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

A)

B)

C)

D)

E)

Question 60

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

A)cholesterol
B)sphingosine
C)chylomicron
D)progesterone
E)cortisone

Question 61

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

Question 62

The most abundant lipids found in membranes are the phosphoglycerides.

Question 63

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

Question 64

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

Question 65

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

Question 66

Bile salts are classified as steroids.

Question 67

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

Question 68

Fatty acids react with long chain alcohols to produce waxes.

Question 69

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

Question 70

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

Question 71

The two essential fatty acids are oleic and linoleic acid.

Question 72

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

Question 73

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

Question 74

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

Question 75

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

A)lipoproteins
B)glycerides
C)phospholipids
D)sphingolipids
E)steroids

Question 76

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.

Question 77

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

Question 78

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