Deck 9: Lipids I

Question 1

What are the characteristics of most unsaturated fatty acids found within a human cell?

A) protonated carboxylic acid and trans double bonds
B) deprotonated carboxylic acid and trans double bonds
C) protonated carboxylic acid and cis double bonds
D) deprotonated carboxylic acid and cis double bonds
E) none of the above

Answer 1

deprotonated carboxylic acid and cis double bonds

Question 2

_____ and _____ have the appropriate geometry to form lipid bilayers whereas _____ tends to form micelles.
Dropdown 1: Fatty acids, waxes, glycerophospholipids
Dropdown 2: triacylglycerols, sphingolipids, isoprenoids
Dropdown 3: fatty acids, triacylglycerols, sphingolipids

Answer 2

glycerophospholipids , sphingolipids,fatty acids

Question 3

With respect to polarity, membrane lipids can be described as ______.

Answer 3

amphiphiles

Question 4

A type of lipid that commonly forms a waterproof barrier and is composed of a fatty acid and a fatty alcohol is called a _____.

A) terpenoid
B) ganglioside
C) capsaicin
D) steroid
E) wax

Question 5

The _____ are a class of amphipathic molecules that constitute the major lipid components of the cell membrane.

Question 6

Which of the following terms describes all glycerophospholipid?

A) zwitterionic
B) amphipathic
C) nonpolar
D) amphoteric
E) none of the above

Question 7

The myelin sheath contains high levels of _____.

Question 8

Identify the compound below.

A) glycerophospholipid
B) sphingosine
C) ceramide
D) spingomylelin
E) ganglioside

Question 9

Which of the following structures correctly represents a glycerophospholipid?

A) structure A
B) structure B
C) structure C
D) structure D
E) none of the above

Question 10

The most notable difference between _____ and other lipids is the presence of four fused rings.

A) cholesterol
B) arachidonic acid
C) ganglioside
D) plasmalogen
E) triacylglycerol

Question 11

Members of the _____ family have four fused, nonplanar rings and a C3-OH group.

Question 12

Eicosanoids are 20-carbon compounds derived from _____.

Question 13

What is the product of fatty acid activation?

A) acyl adenylate
B) pyrophosphate
C) acyl-CoA
D) acyl ester
E) acyl-carnitine

Question 14

What transport system moves activated fatty acids from the cytosol to the mitochondrial matrix?

A) triacylglycerol shuttle
B) glycerol phosphate shuttle
C) acyl adenylate shuttle
D) lipoprotein shuttle
E) carnitine shuttle

Question 15

Considering the figure below, what compound would be formed by action of acyl-CoA dehydrogenase?

A)
B)
C)

D)

E)

Question 16

What coenzyme is required for the complete $\alpha$ -oxidation of a polyunsaturated fatty acid?

A) NADPH
B) NADP⁺
C) NADH
D) FADH₂
E) all of the above

Question 17

During $\beta$ -oxidation of an odd-chain fatty acid, the last three carbon atoms from the oxidized fatty acid enter the citric acid cycle as _____.

A) propionyl-CoA
B) methylmalonyl-CoA
C) succinyl-CoA
D) succinate
E) fumarate

Question 18

The $\beta$ -oxidation of odd-numbered fatty acids results in _____ as a final product.

Question 19

Each round of $\beta$ -oxidation of a saturated fatty acyl-CoA produces _____.

A) 1 NADH, 1 FADH₂, 1 CO₂, 1 acetyl-CoA
B) 1 NADH, 1 FADH₂, 1 acetyl-CoA
C) 1 NADH, 1 FADH₂, 2 acetyl-CoA
D) 1 NADH, 1 FADH₂, 1 H₂O, 1 acetyl-CoA
E) 2 NADH, 1 FADH₂, 1 acetyl-CoA

Question 20

How many ATP can be produced by the complete oxidation of palmitoleic acid, a 16-carbon monounsaturated fatty acid, considering that the fatty acid must first be activated?

A) 26.5
B) 96.5
C) 104.5
D) 106.5
E) none of the above

Question 21

What are the $\beta$ -oxidation products of stearic acid, a saturated fatty acid with 18 carbons?

A) 9 NADH, 9 FADH₂, 9 acetyl-CoA
B) 9 NADH, 8 FADH₂, 9 acetyl-CoA
C) 8 NADH, 9 FADH₂, 9 acetyl-CoA
D) 8 NADH, 8 FADH₂, 9 acetyl-CoA
E) 8 NADH, 7 FADH₂, 9 acetyl-CoA

Question 22

The conversion of 3-hydroxybutyrate to two molecules of acetyl-CoA produces 1 NADH and consumes 1 equivalent of ATP. What is the net ATP yield from the complete oxidation of 3-hydroxybutyrate?

A) 1.5
B) 11.5
C) 13.5
D) 21.5
E) 23.5

Question 23

Fatty acid oxidation occurs in the _____; fatty acid synthesis occurs in the _____.

A) mitochondria; cytosol
B) mitochondria; lysosome
C) lysosome; Golgi apparatus
D) cytosol; Golgi apparatus
E) mitochondria; endoplasmic reticulum

Question 24

Which enzyme is the rate-determining step for fatty acid synthesis?

A) ATP-citrate lyase
B) trans acylase
C) 3-ketoacyl-ACP reductase
D) 3-hydroxyacyl-ACP dehydrase
E) acetyl-CoA carboxylase

Question 25

The activation of acetyl-CoA for fatty acid synthesis is achieved by converting the acetyl-CoA into _____.

A) propionyl-CoA
B) malonyl-CoA
C) acetoacetyl-CoA
D) HMG-CoA
E) $\beta$ -hydroxybutyryl-CoA

Question 26

Acetyl-CoA carboxylase requires the coenzyme _____ as well as _____ as an energy source.

A) FADH₂; acyl-CoA hydrolysis
B) NADPH; GTP
C) biotin; ATP
D) coenzyme A; GTP
E) thiamine pyrophosphate; acyl-CoA hydrolysis

Question 27

Fatty acid synthesis requires both acetyl-CoA and _____ as initiator molecules.

Question 28

Acyl carrier protein (ACP) contains a _____ prosthetic group.

Question 29

Which of the following is the active donor of carbon units in fatty acid biosynthesis?

A) acetyl CoA
B) malonyl CoA
C) palmitic acid
D) propionyl CoA
E) ceramides

Question 30

If a reaction that included all of the enzymes involved in fatty acid synthesis was supplied with excess ATP, NADPH, acetyl-CoA, and ¹⁴CO₂ (where the carbon was a 14C-label), where would the labeled carbon appear in the finished fatty acid?

A) odd-numbered carbons
B) even-numbered carbons
C) every third carbon
D) every fifth carbon
E) no carbons would be labeled

Question 31

Free fatty acids bind to _____ for circulation in the bloodstream.

Question 32

The molecules acetoacetate, acetone, and d- $\beta$ -hydroxybutyrate are metabolic fuels termed _____.

Question 33

Ketone bodies are produced in the _____ and used by the _____ only under conditions such as a prolonged fast.

A) liver; heart
B) liver; brain
C) liver; skeletal muscle
D) kidneys; heart
E) kidneys; brain

Question 34

Which of the following is the primary building block for the synthesis of molecules such as cholesterol or ubiquinone?

A) phosphatidylcholine
B) palmitic acid
C) choline
D) isoprene
E) sphingosine

Question 35

An enzyme that is inhibited by many of the most widely used and effective cholesterol-lowering drugs is _____.

A) phospholipase a2
B) hormone-sensitive lipase
C) HMG CoA reductase
D) desaturase
E) glycerol kinase

Question 36

What class of lipid is squalene, the precursor to cholesterol?

A) isoprenoid
B) fatty acid
C) steroid
D) wax
E) triacylglycerol

Question 37

Cholesterol is converted into _____, a molecule that aids in the absorption of dietary lipids.

A) aldosterone
B) cortisol
C) $\beta$ -estradiol
D) progesterone
E) cholates