Deck 5: Lipids

Question 1

An individual whose diet includes foods fried in vegetable oil,flaxseed oil supplements,and very little fish will have an abundance of which category of fatty acids?

A)n-3
B)n-6
C)n-7
D)n-9

Answer 1

B

Question 2

Gastric lipase works best in which environment?

A)alkaline
B)neutral
C)acidic
D)either alkaline or acidic

Answer 2

C

Question 3

Cholesterol serves as a precursor for all of the following EXCEPT ____.

A)phospholipids
B)estrogens and androgens
C)bile acids
D)vitamin D

Answer 3

A

Question 4

What is the best description of the action of bile?

A)Bile hydrolyzes ester bonds of the triacylglycerols.
B)Bile anchors into dietary lipid so that pancreatic lipase can act.
C)Bile emulsifies dietary lipid to increase its surface area.
D)Bile digests the ester bond of the dietary cholesteryl ester.

Question 5

Which type of acid is linoleic acid?

A)n-9
B)n-7
C)n-6
D)n-3

Question 6

What is the most common lipid found in animals that is characterized by a four-ring core structure?

A)prostaglandins
B)leukotrienes
C)cholesterol
D)glycolipids

Question 7

Mono- and diacylglycerols are used in processed foods as ____.

A)thickening agents
B)emulsifying agents
C)antioxidants
D)food preservatives

Question 8

Which fatty acid is considered essential and must be supplied by the diet?

A)arachidonic acid
B)omega-9 fatty acid
C)linoleic acid
D)oleic acid

Question 9

Triacylglycerols with saturated fatty acids of longer chain length tend to be ____ at room temperature.

A)liquid oils
B)emulsified
C)nonesterified fats
D)solid fats

Question 10

The highest concentration of sphingolipids is found in cells of the ____.

A)cardiovascular system
B)digestive system
C)reproductive system
D)central nervous system

Question 11

Which unsaturated fatty acid is found in fish oil?

A)alpha-linolenic
B)eicosapentaenoic
C)arachidonic
D)oleic

Question 12

Undigested lipid in the stomach creates satiety because it ____.

A)speeds the rate of emptying of the stomach
B)delays the rate of emptying of stomach contents
C)enhances gastric motility
D)suppresses GIP and secretin

Question 13

Cocoa butter contains which saturated fatty acid?

A)palmitic
B)stearic
C)arachidic
D)myristic

Question 14

In what form is most body fat stored?

A)fatty acids
B)triacylglycerols
C)cholesterol
D)phospholipids

Question 15

The fatty acid chains found in foods and body tissues range from ____ carbon atoms in length.

A)1 to 3
B)2 to 6
C)3 to 12
D)4 to 24

Question 16

Phosphatidylinositol is a membrane phospholipid that can ____.

A)anchor membrane proteins that are attached to lipids
B)stabilize the cytoplasm
C)create pores in the cell membrane
D)act as a receptor for viruses

Question 17

Carbon-carbon double bonds in the trans form ____.

A)result in a kinking of the fatty acid into a U-shape
B)extend the fatty acid into a linear shape
C)are required to create saturated fatty acids
D)are the hallmark of essential fatty acids

Question 18

Lipids are different from other major nutrients because they ____.

A)contain carbon, hydrogen, and oxygen
B)are soluble in organic solvents
C)provide energy
D)are digestible

Question 19

Fat digestion does not require ____.

A)pancreatic lipase
B)colipase
C)bile
D)leucine

Question 20

How does orlistat reduce absorption of dietary fat?

A)by replacing dietary fat with a synthetic, indigestible substitute
B)by inhibiting the activity of pancreatic lipase
C)by binding free fatty acids and causing their excretion
D)by inhibiting HMG-CoA reductase

Question 21

Apolipoproteins are unable to ____.

A)stimulate enzymatic reactions that regulate the metabolic functions of lipoproteins
B)stabilize circulating lipoproteins in the blood
C)decrease the density of the lipoprotein
D)confer specificity for recognition by receptors on cells

Question 22

Which one of the following events will occur in the signaling pathway mediated by natriuretic peptides?

A)increased intracellular cAMP activates protein kinase G
B)ANP and BNP bind to type-B natriuretic peptide receptors
C)activated receptors interact with guanylyl cyclase
D)activated guanylyl cyclase converts intracellular AMP to cAMP

Question 23

Which of the following lipoproteins is normally NOT present in blood in the fasting state?

A)VLDL
B)chylomicrons
C)LDL
D)HDL

Question 24

Lipolysis is stimulated by ____.

A)epinephrine alone
B)epinephrine and natriuretic peptides
C)natriuretic peptides alone
D)norepinephrine and epinephrine

Question 25

Polymolecular aggregates called micelles are small enough to ____.

A)enter the enterocytes
B)stabilize circulating lipoproteins in the blood
C)enter the intramicrovillus spaces to interact with the brush border
D)confer specificity for recognition by receptors on cells

Question 26

In response to excess dietary carbohydrate and chylomicron remnants,which substances does the liver synthesize to transport triacylglycerol?

A)chylomicrons
B)VLDLs
C)LDLs
D)HDLs

Question 27

Which of the following lipoproteins is the major carrier of cholesterol to tissues for use in construction of membranes or steroid hormones?

A)VLDL
B)HDL
C)LDL
D)chylomicrons

Question 28

Choose the list of molecules that would be found in a micelle.

A)vitamin A (retinol), glycerol, 2-monoacylglycerols, linolenic acid
B)glycerol, butyric acid, cholesterol, 2-monoacylglycerols
C)linolenic acid, 2-monoacylglycerols, cholesterol, fat-soluble vitamins
D)fructose, glucose, glycerol, vitamin A

Question 29

In the small intestine,which enzyme hydrolytically activates a pancreatic zymogen so that lipid digestion can occur?

A)pepsin
B)trypsin
C)colipase
D)maltase

Question 30

Abnormal LDL receptors fail to remove cholesterol from the bloodstream,resulting in ____.

A)suppression of acyl-CoA cholesteryl acyl transferase (ACAT)
B)suppression of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase
C)hypertriglyceridemia
D)familial hypercholesterolemia

Question 31

What are some products of the reaction catalyzed by pancreatic lipase?

A)2-monoacylglycerols, free fatty acids
B)free fatty acids, glycerol, cholesterol
C)2-monoacylglycerols, free fatty acids, phospholipids
D)free fatty acids, glycerol, cholesteryl esters

Question 32

Which organ provides the major site for lipoprotein formation from exogenously derived lipids?

A)pancreas
B)adipose tissue
C)intestine
D)liver

Question 33

What is the carrier for medium-chain fatty acids in portal circulation?

A)triacylglycerides
B)cholesterol
C)chylomicrons
D)albumin

Question 34

Trans fatty acids are considered to be dangerous to human health because they ____.

A)elevate serum glucose levels
B)raise LDL-C
C)lower HDL-C
D)raise LDL-C and lower HDL-C at the same time

Question 35

Choose the correct sequential order for participants in lipid digestion.

A)colipase, pancreatic lipase, bile, micelles
B)bile, colipase, pancreatic lipase, micelles
C)bile, enterokinase, colipase, micelles
D)micelles, bile, pancreatic lipase, colipase

Question 36

Reverse cholesterol transport that removes cholesterol from peripheral cells and returns it to the liver is carried out by ____.

A)LDL
B)HDL
C)VLDL
D)lipoprotein lipase

Question 37

The process by which bile salts are absorbed in the small intestine and return to the liver is called ____ of the bile salts.

A)micelle induction
B)resecretion
C)conjugation
D)enterohepatic circulation

Question 38

Which apolipoprotein is key to the delivery of triacylglycerol to tissues?

A)apoC-2
B)apoA-1
C)apoE
D)apoB-100

Question 39

The key to the cell's internalization of LDL is the interaction between the receptors and ____.

A)cholesterol acyltransferase
B)HMG-CoA reductase
C)apolipoprotein B-100
D)apolipoprotein C-100

Question 40

Where does pancreatic lipase begin to work?

A)the duodenum
B)the stomach
C)the large intestine
D)the last portion of the small intestine

Question 41

HMG-CoA reductase is a key enzyme in the synthesis of cholesterol from acetyl-CoA.

Question 42

Ketogenesis would be the HIGHEST ____.

A)after a high-CHO meal
B)after a high-protein meal
C)after a high-fat meal
D)during prolonged starvation

Question 43

Once a micelle,containing lipids and lipid-soluble compounds,enters the enterocyte,it is referred to as a chylomicron.

Question 44

One of the primary functions of a phospholipid is possible because of its structure,which allows it to be both hydrophobic and hydrophilic.

Question 45

What is formed when fatty acids are oxidized in the mitochondria (i.e.,what is the end product of beta-oxidation)?

A)glycerol
B)pyruvate
C)acetyl-CoA
D)triacylglycerol

Question 46

When fatty acids are completely oxidized,the end products are ____.

A)fatty acid and glycerol
B)carbon dioxide, energy, and water
C)urea and acetate
D)carbon, hydrogen, and phosphate

Question 47

Ketogenesis is the synthesis of ketone bodies from fatty acids for energy under conditions of excess glucose,such as in the fed state.

Question 48

Essential fatty acids are classified as such because we cannot synthesize them from other fatty acids and they are required for the synthesis of prostaglandins,thromboxanes,and leukotrienes.

Question 49

The key organ in clearing (i.e.,breaking down)lipoproteins is the liver.

Question 50

The conversion of linoleic acid (18:2)to arachidonic acid (20:4)involves the addition of two carbons to the methyl end and two double bonds at the n-3 and n-6 positions of the omega end.

Question 51

What is the carrier molecule needed for mitochondrial membrane transport of long-chain fatty acids and their CoA derivatives?

A)carnitine
B)creatine
C)creatinine
D)cysteine

Question 52

Unlike long-chain fatty acids,short-chain fatty acids from the diet leave the enterocyte via the portal vein and go directly to the liver.

Question 53

Ketones are produced from ____.

A)cholesterol
B)hormones
C)amino groups
D)acetyl-CoA

Question 54

Most Americans consume approximately half of their total dietary lipid as triacylglycerols,and the other half as cholesterol; very little is taken in as phospholipids.

Question 55

The HDL accomplishes its function in reverse cholesterol transport in two ways.Choose the phrase that does NOT describe one of these.

A)increased apoC-2 activity to reduce its triacylglycerol content
B)increased activity of LCAT on vascular endothelial cells
C)increased activity of transferring cholesterol to other lipoproteins
D)using its apoE component to bind to LDL receptors

Question 56

Which drug therapy is associated with reduced cholesterol synthesis in the liver?

A)insulin
B)niacin
C)gene therapy
D)HMG-CoA reductase inhibitors

Question 57

Adipocytes' primary function is to store fat as triacylglycerol; thus,they do not require glycolysis and the TCA cycle for energy needs.

Question 58

What is the normal product of the fatty acid synthase system?

A)triacylglycerol
B)myristate
C)palmitate
D)butyrate

Question 59

What is considered the toxic level of blood ethanol?

A)less than 10 mg/dL
B)11-24 mg/dL
C)25-45 mg/dL
D)50-80 mg/dL

Question 60

What is the most important unsaturated fatty acid serving as a precursor for eicosanoid synthesis?

A)arachidonic acid
B)palmitoleic acid
C)oleic acid
D)linoleic acid

Question 61

Discuss three things that cannot be correct in the notation 18:2?8,9,19 when using the delta system of designating fatty acids.*
*Source: Brody T,Nutritional Biochemistry,2nd ed.Academic Press,San Diego,CA,1999.page 643.

Question 62

Bile is the GI enzyme that hydrolyzes dietary triacylglycerol into free fatty acids and glycerol.

Question 63

Match the lipid with the cardiovascular disease risk.
a.atherogenic fatty plaque
b.hypercholesterolemia
c.raise LDL-C/lower HDL-C
d.structural homology with plasminogen; increased risk of CVD
e.increases LDL's affinity for macrophage receptors causing plaque
cholesterol

Question 64

Moderate alcohol intake is associated with an increased risk of coronary heart disease.

Question 65

Match the enzymes with their functions in lipid metabolism.
a.creates a double bond in a fatty acid
b.removes triacylglycerol from plasma
c.mobilizes stored triacylglycerols from adipocytes
d.rate-limiting enzyme in cholesterol synthesis
e.creates prostaglandins
HMG-CoA reductase

Question 66

Explain the regulation of the allosteric enzyme acetyl-CoA carboxylase by citrate and palmitoyl-CoA.

Question 67

Describe the transport system that allows for fatty acid synthesis and the molecules involved in transferring acetyl-CoA into cytoplasm.

Question 68

Match the enzymes with their functions in lipid metabolism.
a.creates a double bond in a fatty acid
b.removes triacylglycerol from plasma
c.mobilizes stored triacylglycerols from adipocytes
d.rate-limiting enzyme in cholesterol synthesis
e.creates prostaglandins
lipoprotein lipase

Question 69

Describe fat metabolism in the adipose cell following a meal.

Question 70

Match the enzymes with their functions in lipid metabolism.
a.creates a double bond in a fatty acid
b.removes triacylglycerol from plasma
c.mobilizes stored triacylglycerols from adipocytes
d.rate-limiting enzyme in cholesterol synthesis
e.creates prostaglandins
intracellular lipase

Question 71

Match the enzymes with their functions in lipid metabolism.
a.creates a double bond in a fatty acid
b.removes triacylglycerol from plasma
c.mobilizes stored triacylglycerols from adipocytes
d.rate-limiting enzyme in cholesterol synthesis
e.creates prostaglandins
cyclo-oxygenase

Question 72

The regulation of fatty acid synthesis and oxidation is closely linked to carbohydrate status.

Question 73

Match the enzymes with their functions in lipid metabolism.
a.creates a double bond in a fatty acid
b.removes triacylglycerol from plasma
c.mobilizes stored triacylglycerols from adipocytes
d.rate-limiting enzyme in cholesterol synthesis
e.creates prostaglandins
desaturase

Question 74

Match the lipid with the cardiovascular disease risk.
a.atherogenic fatty plaque
b.hypercholesterolemia
c.raise LDL-C/lower HDL-C
d.structural homology with plasminogen; increased risk of CVD
e.increases LDL's affinity for macrophage receptors causing plaque
lipoprotein (a)

Question 75

Match the lipid with the cardiovascular disease risk.
a.atherogenic fatty plaque
b.hypercholesterolemia
c.raise LDL-C/lower HDL-C
d.structural homology with plasminogen; increased risk of CVD
e.increases LDL's affinity for macrophage receptors causing plaque
apolipoprotein E

Question 76

Match the lipid with the cardiovascular disease risk.
a.atherogenic fatty plaque
b.hypercholesterolemia
c.raise LDL-C/lower HDL-C
d.structural homology with plasminogen; increased risk of CVD
e.increases LDL's affinity for macrophage receptors causing plaque
saturated and unsaturated fatty acids

Question 77

Fatty acids are converted into glucose by gluconeogenesis and used for energy during starvation.

Question 78

Match the lipid with the cardiovascular disease risk.
a.atherogenic fatty plaque
b.hypercholesterolemia
c.raise LDL-C/lower HDL-C
d.structural homology with plasminogen; increased risk of CVD
e.increases LDL's affinity for macrophage receptors causing plaque
trans fatty acids

Question 79

Brown fat contains more mitochondria than white fat and is involved in thermogenesis.

Question 80

Describe the process of fat storage (triacylglycerol synthesis)AND mobilization (triacylglycerol lipolysis)in adipose tissue-be sure to include how these processes are regulated (i.e.,the signals involved).