Deck 26: Lipids

Question 1

What is the structure of choline, a component of phosphatidylcholine phospholipids?

A)1
B)2
C)3
D)4

Answer 1

3

Question 2

Which of the following is not found in a fluid mosaic lipid bilayer?

A)phospholipid
B)cholesterol
C)protein
D)nucleic acid

Answer 2

nucleic acid

Question 3

Which of the following fatty acids has the highest melting point?

A)lauric acid
B)myristic acid
C)palmitic acid
D)stearic acid

Answer 3

stearic acid

Question 4

What is the R/S configuration of C-8 and C-12 of prostaglandin F_{2 $\alpha$}
?

A)8R,12R
B)8R,12S
C)8S,12R
D)8S,12S

Question 5

Which of the following is not an intermediate in the biosynthesis of cholesterol?

A)acetyl coenzyme A
B)isopentenyl pyrophosphate
C)squalene
D)arachidonic acid

Question 6

How many triglycerides (including stereoisomers) are there which contain two molecules of stearic acid, and one of myristic acid?

A)3
B)6
C)9
D)12

Question 7

What is the biological precursor of prostaglandins?

A)stearic acid
B)arachadonic acid
C)oleic acid
D)linolenic acid

Question 8

What is the E/Z configuration of the carbon-carbon double bonds at C-5 and C-13 of prostaglandin F_{2 $\alpha$}
?

A)5E,13E
B)5E,13Z
C)5Z,13E
D)5Z,13Z

Question 9

What is the structure of inositol, a component of phospholipids?

A)1
B)2
C)3
D)4

Question 10

What is the structure of stearic acid?

A)CH₃(CH₂)₁₆COOH
B)CH₃(CH₂)₇CH=CH(CH₂)₇COOH
C)CH₃(CH₂)₁₈COOH
D)CH₃CH₂(CH=CHCH₂)₃(CH₂)₆COOH

Question 11

Which of the following is not an eicosanoid?

A)prostaglandin E₂
B)leukotriene C₄
C)thromboxane A₂
D)cholesterol

Question 12

What is the structure of oleic acid?

A)CH₃(CH₂)₁₆COOH
B)CH₃(CH₂)₇CH=CH(CH₂)₇COOH
C)CH₃(CH₂)₁₈COOH
D)CH₃CH₂(CH=CHCH₂)₃(CH₂)₆COOH

Question 13

How many triglycerides (including stereoisomers) are there which contain one molecule of stearic acid, one of myristic acid and one of arachidic acid?

A)3
B)6
C)9
D)12

Question 14

Which of the following is a synthetic detergent?

A)sodium 4-dodecylbenzenesulfonate
B)N-(2-hydroxyethyl)dodecanamide
C)sodium perborate dihydrate
D)sodium palmitate

Question 15

Which of the following is not true?

A)sodium soaps are prepared by saponification of triglycerides
B)a by-product of the saponification of triglycerides is glycerol
C)soap molecules assemble into micelles
D)grease molecules absorb on to the surface of micelles

Question 16

What is the approximate value of pK_a of a bile acid?

A)-4
B)1
C)5
D)25

Question 17

Which of the following fatty acids has the highest melting point?

A)stearic acid
B)oleic acid
C)linoleic acid
D)linolenic acid

Question 18

What functional group of the protein opsin reacts with retinal to form rhodopsin, a light-sensitive pigment?

A)carboxylic acid
B)amide
C)1 ^$\circ$ amine
D)alcohol

Question 19

Which of the following processes is used to harden an oil to give a fat?

A)oxidation
B)hydrogenation
C)hydrolysis
D)hydration

Question 20

What is the R/S configuration of C-9 and C-11 of prostaglandin F_{2 $\alpha$}
?

A)9R,11R
B)9R,11S
C)9S,11R
D)9S,11S

Question 21

Consider the following structures. Use these to answer the following questions by placing the appropriate Roman numerical in the blank.
Saponification followed by protonation of structure _____ produces two moles of the salt of stearic acid and one mole of the salt of oleic acid.

Question 22

An example of a cationic detergent is shown below.

Question 23

Cell membranes, which form an effective barrier to the passage of ions and other components into and out of the cell, are composed of a lipid bilayer.

Question 24

The major lipid component of cell membranes is phospholipids.

Question 25

The general formula for a fat or oil is shown below.

Question 26

Consider the following substance. The melting point of the above substance will be _________ than that of the substance listed below.

Question 27

The main difference between fats and oils is that oils contain a lower percentage of unsaturated alkyl chains.

Question 28

Ca⁺², Mg⁺², and/or Fe⁺³ are responsible for producing soap scum in water.

Question 29

The structure of andosterone is given below. The following is produced when andosterone is treated with NaBH₄ in ethanol.

Question 30

Salts of long chain fatty acids are called detergents.

Question 31

Compounds that are obtained from the saponification of triglycerides are glycerol and fatty acid salts.

Question 32

The structure of acetyl-CoA is shown below and is a building block from which steroids are produced.

Question 33

Lipids are substances that are in water and in nonpolar organic solvents. Enter the answers separated by a comma.

Question 34

All steroids have the common skeleton shown below.

Question 35

The chiral centers in $\alpha$ -santonin are indicated by asterisks in the following.

Question 36

Consider the following. Structure ____ would be classified as an synthetic detergent.

Question 37

Consider the following structures. Use these to answer the following questions by placing the appropriate Roman numerical in the blank.
Saponification followed by protonation of structure _____ produces three moles of the same saturated fatty acid.

Question 38

The number of carbon atoms in the unsaturated fatty acid from which prostaglandins are derived is _____.

Question 39

Consider the following. Structure ____ would be classified as an ordinary soap.

Question 40

CH₃(CH₂)₁₂CO₂H would be expected to be found in higher concentration in butter versus olive oil.

Question 41

What are the roles of LDL and HDL? Which one is "good" cholesterol, which one is bad"?

Question 42

Circle the hydrophilic part of sodium 4-dodecylbenzenesulfonate, a synthetic detergent, and put a rectangle around the hydrophobic part.

Question 43

Describe how the structure of a phospholipid differs from that of a trigyceride fat, and what influence this difference has on the interaction of these molecules with water.

Question 44

The following tetracylic structure is common to steroids, an importnat class of biomolecules that have a number of sterocenters. Modify the structure on the right by placing the hydrogen atoms and methyl groups to accurately depict the structure on the left (including steeochemistry).

Question 45

Explain the formation of "soap scum", formed in areas which have "hard" water. What chemical reaction takes place, and what physical process results?

Question 46

Why do hydrogenated fats have higher boiling points than the triglycerides from which they are derived?

Question 47

Male sex hormones like testosterone are called _____________.

Question 48

Briefly describe the chemical reaction that is used to "harden" a vegetable oil to give a fat.

Question 49

Female sex hormones like estrone are called _____________.

Question 50

Circle the hydrophilic part of sodium palmitate, a soap that is the sodium salt of a fatty acid, and put a rectangle around the hydrophobic part.

Question 51

Provide the general structure of a triglyceride.

Question 52

The family of C₂₀ lipids that contain a five-membered ring with two long side chains are called ____________________.

Question 53

Arachidonic acid is a C₂₀ acid that is involved in the biosynthesis of prostaglandins, an important class of biomolecules. Provide the IUPAC name of arachidinic acid.

Question 54

When soaps disperse in water, the long hydrocarbon tails cluster together in a hydrophobic ball, while the ionic heads on the surface of the cluster stick out into the water. These spherical clusters are called ___________.