Deck 11: Lipids and Membranes

Question 1

In which solvent would lipids be most soluble?

A) hexane
B) water
C) methyl alcohol
D) ethyl alcohol

Answer 1

hexane

Question 2

Triglycerides composed of glycerin and mostly polyunsaturated fatty acid residues are likely to be ___ at room temperature.

A) solid fats
B) liquid oils
C) gases
D) waxes

Answer 2

liquid oils

Question 3

Shown below is the structure of the fatty acid, lauric acid:
The boxed portion is considered to be both

A) hydrophilic and hydrophobic.
B) polar and hydrophobic.
C) polar and hydrophilic.
D) nonpolar and hydrophilic.

Answer 3

polar and hydrophilic.

Question 4

The structure of the fatty acid, palmitic acid, is
Palmitic acid is a(n) ___ fatty acid.

A) saturated
B) monounsaturated
C) polyunsaturated
D) waxy

Question 5

The fatty acid, palmitoleic acid, is
Notice the double bond. Palmitoleic acid is a ___ fatty acid.

A) saturated
B) monounsaturated
C) polyunsaturated
D) waxy

Question 6

Fatty acids can produce ions that are ___.

A) highly charged at the tail
B) nonpolar
C) amphipathic
D) hydrophobic

Question 7

The melting point of lauric acid, CH₃(CH₂)₁₀CO₂H , is 43 $\degree$ C and the melting point of stearic acid (CH₃(CH₂)₁₆CO₂H) is 69 $\degree$ C. Which of the following statements best explains why the melting point of lauric acid is lower than the melting point of stearic acid?

A) The hydrophobic tail of lauric acid is longer than the hydrophobic tail of stearic acid.
B) Stearic acid is soluble in water and lauric acid is not soluble in water.
C) Stearic acid is a fatty acid, whereas lauric acid is not a fatty acid.
D) The London force interactions are stronger in stearic acid than they are in lauric acid.

Question 8

The skeletal structure of Arachidonic acid, an essential fatty acid, is provided below. Arachidonic acid is best classified as:

A) Omega-3-fatty acid
B) Omega-6-fatty acid
C) Saturated fatty acid
D) Wax

Question 9

In which solvent below would lipids be least soluble?

A) hexane
B) water
C) methyl alcohol
D) ethyl alcohol

Question 10

The structure of palmitate ion derived from the fatty acid, palmitic acid, is
Its molecular structure has both polar and nonpolar portions. Therefore, palmitate ion is classified as ___.

A) hydrophobic
B) lipophobic
C) hydrophilic
D) amphipathic

Question 11

Omega-3 and Omega-6-fatty acids are essential fatty acids. Which of the following statement best describes these essential fatty acids?

A) They are very soluble in water.
B) They are saturated fatty acids that the body absorbs faster.
C) They are not produced in the body and must be obtained through diet.
D) They are waxes found in the body.

Question 12

The skeletal structure of docosahexaenoic acid, an essential fatty acid, is provided below. Docosahexaenoic acid is best classified as:

A) Omega-3-fatty acid
B) Omega-6-fatty acid
C) Saturated fatty acid
D) Wax

Question 13

The structure below is best classified as a ___.

A) triglyceride
B) wax
C) steroid
D) phospholipid

Question 14

Waxes are compounds that are

A) the result of the reaction of a fatty acid and sodium hydroxide.
B) extremely hydrophilic due to the head end of the compound.
C) mixtures of water insoluble compounds, especially esters.
D) small compounds produced when short chain fatty acids react with an alcohol.

Question 15

Compounds found in feathers and leaves of most plants, which serve as protective coatings to keep water from entering or leaving an organism, are ___.

A) glycolipids
B) steroids
C) waxes
D) sphingolipids

Question 16

Carnauba wax is widely used for high-gloss car and floor polishes. A major component of carnauba wax ester is provided below. The condensed structure of the alcohol from which carnauba wax ester is formed is:

A)
B)
C)
D)

Question 17

Identify the class of lipid to which the following molecule belongs.

A) fatty acid
B) triglyceride
C) wax
D) glycerophospholipid

Question 18

Saponification

A) is a hydrolysis reaction.
B) results in the production of triglycerides.
C) is used to store energy for later use.
D) is a reaction found in plant metabolism.

Question 19

How many molecules of H₂ will react with one molecule of the following triglyceride?

A) 1
B) 3
C) 4
D) 6

Question 20

The effect of the hydrogenation of oils is to

A) remove double bonds.
B) cause the oils to remain as liquids.
C) make the oils boil at a lower temperature.
D) make the oils oxidize.

Question 21

Oleic acid has the formula CH₃(CH₂)₇(CH = CH(CH₂)₇CO₂H. The carbon -carbon double bond in oleic acid is usually cis. Compared to saturated fatty acids with the same number of carbon atoms, cis-oleic acid will have

A) a lower melting point due to a kink in the hydrocarbon tail.
B) stronger London forces and a higher melting point.
C) bonds that fit in the packing of the hydrophobic tails, creating stronger interaction between molecules.
D) no reaction with hydrogen in the presence of platinum catalyst.

Question 22

Animal fats and vegetable oils become rancid when exposed to air because

A) they are hydrogenated to form saturated fatty acids.
B) carbon-carbon double bonds are oxidized in air, producing small organic molecules.
C) they form amino acids in air.
D) they are partially hydrogenated.

Question 23

Identify the class of lipid to which the following molecule belongs.

A) sphingophospholipid
B) triglyceride
C) cholesterol
D) glycerophospholipid

Question 24

Which of the following is one of the products formed when the lipid below is saponified?

A)
B)
C)
D)

Question 25

Phospholipids ___.

A) are really a wax
B) are very polar on both ends
C) contain a sugar, which may be simple or a chain
D) are part of the structure of cell membranes

Question 26

Determine the number of molecules of H₂ that will react with one molecule of the following triglyceride.

A) three
B) four
C) six
D) five

Question 27

Because of the components that are found in phospholipids, the phospholipid molecules

A) are long molecules with multiple polar points.
B) have a head that is nonpolar, as is the tail.
C) have a polar end and a nonpolar end.
D) have two ends that are nonpolar with a polar middle.

Question 28

The phosphate head group of phospholipids is ___ and is found on the ___ of a membrane's lipid bilayer.

A) hydrophilic/inside
B) hydrophilic/outside
C) hydrophobic/inside
D) hydrophobic/outside

Question 29

The difference between the sphingolipids and the glycerophospholipids is that the sphingolipids

A) have three alcohol residues that replace the fatty acid residues.
B) have one phosphate, but it is attached to the fatty acid residue, not the glycerol.
C) have three phosphates, not one, and they are attached to all of the fatty acids.
D) include sphingosine with a phosphate attached to it, and an alcohol residue.

Question 30

The lipid that is a cell surface receptor for hormones and drugs is a

A) glycerophopholipid.
B) ganglioside.
C) sphingomyelin.
D) cerebroside.

Question 31

Lecithin is found in egg whites and can be used as an emulsifying agent to keep mayonnaise from separating. Lecithin is classified as a ___.

A) phospholipid
B) wax
C) steroid
D) glycolipid

Question 32

Sphingomyelins are found in ___.

A) waxes
B) egg whites
C) skin cells
D) nerve cell membranes

Question 33

How many products are obtained when the phospholipid below is saponified?

A) 2
B) 5
C) 3
D) 6

Question 34

The structure shown below represents which of the following?

A) sphingosine
B) glycerophospholipid
C) triglyceride
D) sphingoglycolipid

Question 35

The structure shown below represents which of the following?

A) sphingophospholipid
B) shingoglycolipid
C) glycerophospholipid
D) disaccharide

Question 36

The structure shown below is the skeletal structure of a ___.

A) wax
B) triglyceride
C) phospholipid
D) steroid

Question 37

The steroid that is the raw material for the production of other steroids is

A) triglyceride.
B) cholesterol.
C) progesterone.
D) eicosanoid.

Question 38

The hormone that is the starting point for the production of the adrenocorticoid hormones and testosterone is

A) progesterone.
B) estrogen.
C) cholesterol.
D) chylomicrons.

Question 39

Which of the following is released from the gallbladder into the small intestine to aid digestion by dispersing dietary lipids into fine emulsions?

A) Bile salts
B) cholesterol
C) eicosanoids
D) phospholipids

Question 40

Cholesterol contains nonpolar rings and hydrocarbon chains, and also has an alcohol group (-OH). Which statement below is correct?

A) The molecule is totally hydrophobic.
B) Most of the molecule is hydrophobic with the -OH being hydrophilic.
C) The molecule is totally hydrophilic.
D) Cholesterol molecules would line up with the alcohol group attracted by the rings.

Question 41

Which of the following compounds share the steroid ring structure?

A) cholesterol and phospholipids
B) phospholipids and arachidonic acid
C) arachidonic acid and bile salts
D) bile salts and cholesterol

Question 42

Anabolic steroids can cause some serious health problems including

A) reduced circulation to the brain and liver.
B) muscle atrophy and blocked arteries.
C) high blood pressure and testicular atrophy.
D) the interruption of nerve impulses and reduced intestinal function.

Question 43

The thromboxanes are

A) anabolics that may be involved in increasing blood pressure.
B) eicosanoids that are involved in blood clotting.
C) adrenocroticoids that aid in the activation of sex hormones.
D) lipids that have the capacity to cause membranes to grow.

Question 44

___ is the eicosanoid involved in blood clotting.

A) Prostaglandin
B) Leukotriene
C) Progesterone
D) Thromboxane

Question 45

___ is the eicosanoid involved in muscle contractions.

A) Prostaglandin
B) Leukotriene
C) Progesterone
D) Thromboxane

Question 46

Nonsteroidal anti-inflammatory drugs (NSAIDS) block the actions of the COX enzymes and their production of eicosanoids from ___.

A) steroids
B) arachidonic acid
C) sphingolipids
D) phospholipids

Question 47

The lipid hormones that are derived from arachidonic acid are the ___.

A) arachidonics
B) eicosanoids
C) adrenocorticoid hormones
D) sex hormones

Question 48

Which compounds are responsible for causing pain and inflammation?

A) anabolic steroids
B) adrenocorticoids
C) prostaglandins
D) leukotrienes

Question 49

Which of the following lipids is not derived from cholesterol?

A) progesterone
B) thromboxane
C) cortisol
D) testosterone

Question 50

Eicosanoids are hormones derived from arachidonic acid. Which is not an eicosanoid?

A) prostaglandin
B) leukotriene
C) progesterone
D) thromboxane

Question 51

What is the function of nonsteroidal anti-inflammatory drugs (NSAID)?

A) To interrupt the production of prostaglandins from arachidonic acid.
B) To interfere with the production of anabolic steroids.
C) To facilitate the production of cyclooxygenase.
D) To stimulate the production of leukotrienes.

Question 52

The fluid mosaic model proposes that

A) membranes can move like a fluid.
B) proteins are embedded into the cell membrane.
C) materials that are fluid move across a membrane.
D) the composition of membranes includes a mosaic fluid.

Question 53

Suppose a highly positive ion was attracted to a membrane. At what location would that most likely occur?

A) the head of a lipid
B) the tail of a lipid
C) the nonpolar portion of a protein
D) the double bond located within a lipid

Question 54

Some molecules and ions are transported across a membrane via ___, which requires energy.

A) osmosis
B) diffusion
C) facillitated diffusion
D) active transport

Question 55

Active transport, a function of membranes,

A) requires an input of energy.
B) moves amino acids and small ions across the membrane.
C) requires an input of energy and moves amino acids and small ions across the membrane.
D) None of these choices.

Question 56

Saturated fatty acids have lower melting points than unsaturated fatty acids with the same number of carbon atoms.

Question 57

All commonly occurring fatty acids contain trans alkene groups.

Question 58

Trans fats are produced during the hydrogenation of fats and oils.

Question 59

Sphingolipids are a class of phospholipids.

Question 60

Sphingolipids are amphipathic hydrolysable lipids based on glycerol.

Question 61

Testosterone is produced from arachidonic acid.

Question 62

Low density lipoproteins (LDLs) transport cholesterol and phospholipids from the liver to the cells.

Question 63

Adrenocorticoid hormones are produced from cholesterol.

Question 64

Bile acids are attached to glycerol backbone by ester bonds.

Question 65

Membranes are composed entirely of phospholipids; this factor explains the ease with which facilitated diffusion functions.

Question 66

The hydrophobic end of a phospholipid is the ___ end.

Question 67

___ are used by both plants and animals as waterproofing.

Question 68

___ fats form when vegetable oil, which contain cis-double bonds, undergoes partial hydrogenation.

Question 69

A phospholipid contains a total of ___ fatty acid residues.

Question 70

Glucose is a simple sugar used in the structure of the ___, a class of lipids that includes the cerebrosides.

Question 71

The LDL/HDL ratio should be less than ___ to avoid those problems inherent with high cholesterol.

Question 72

The ___ steroids are associated with growth.

Question 73

___ is the eicosanoid involved in causing pain, inflammation and affects blood pressure.

Question 74

Matching

-Mixtures of water insoluble compounds including esters, alcohols, and alkanes.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification

Question 75

Matching

-Reaction that produces glycerol and fatty acid salts from triglycerides.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification

Question 76

Matching

-Substance that can make or stabilize water insoluble substances as colloids.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification

Question 77

Matching

-An emulsifying agent found in egg white.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification

Question 78

Matching

-Glycolipid found at nerve synapses.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification

Question 79

Matching

-Eicosanoid that causes pain and inflammation.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification

Question 80

Matching

-Eicosanoid that is responsible for muscle contraction.

A) emulsifier
B) facilitated diffusion
C) lecithin
D) leukotriene
E) eicosanoid
F) active transport
G) wax
H) prostaglandin
I) cerebroside
J) saponification