Deck 5: Lipids

Question 1

In what form is most body fat stored?

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

Answer 1

B

Question 2

What antithrombotic n-3 fatty acid is found in fish oil?

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

Answer 2

B

Question 3

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

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

Answer 3

C

Question 4

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

A) liquid oils
B) emulsified
C) non-esterified fats
D) solid fats

Question 5

Choose 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 6

Sphingomyelins are important phospholipids found in the _____.

A) pacemaker of the heart
B) kidney tubules
C) myelin sheath of nerves
D) human blood groups A, B and O

Question 7

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 8

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 9

Which enzyme will act on corn oil in the small intestine?

A) pancreatic lipase
B) lecithin cholesterol acyl transferase
C) cholesterol esterase
D) lipoprotein lipase

Question 10

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 11

The structure below is a _____.

A) triacylglycerol
B) cholesteryl ester
C) phospholipid
D) glycolipid

Question 12

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 13

Phospatidylinositol is a membrane phospholipid that can _____.

A) anchor surface proteins to the plasma membrane
B) create 2 second messengers in cell signaling
C) both a and b
D) none of the above

Question 14

Gastric lipase is important for the suckling infant for all of the following reasons EXCEPT:

A) It can readily penetrate milk fat globules without bile salt stabilization.
B) It hydrolyzes short-chain fatty acids from the sn-3 position.
C) It requires an alkaline environment for optimal activity.
D) It is highly stable in an acid environment.

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

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 17

Glycerophosphatides serve which of the following functions?

A) source of stored energy
B) constituent of cell and organelle membranes
C) precursor for long-chain n-3 fatty acids
D) constituent of myelin sheaths

Question 18

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

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

Question 19

All of the following are required for fat digestion EXCEPT _____.

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

Question 20

What dietary fatty acid family exerts anti-thrombotic properties?

A) n-6
B) n-3
C) n-9
E) saturated

Question 21

Which of the choices listed below is NOT a reaction of the hepatocyte to an excess amount of free cholesterol?

A) increase ACAT activity to store cholesterol
B) decrease HMG-CoA reductase activity
C) down-regulate the apoB-100/E receptors
D) decrease LPL activity

Question 22

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

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

Question 23

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 24

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 25

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

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

Question 26

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 27

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

A) apo-C2
B) apoA-1
C) apoE
D) apoB-100

Question 28

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 29

154 27. What organ provides the major site for lipoprotein formation from exogenously derived lipids?

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

Question 30

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 31

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 32

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 33

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, vitamin D
D) fructose, glucose, glycerol, vitamin A

Question 34

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 35

In response to excess dietary carbohydrate and chylomicron remnants, the liver synthesizes _____ to transport triacylglycerol.

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

Question 36

The process by which bile salts are absorbed in the ileum and return to the liver is called _____ of the bile salts.

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

Question 37

153 28. All of the following are functions of apolipoproteins EXCEPT:

A) stimulating enzymatic reactions that regulate the metabolic functions of lipoproteins.
B) stabilizing circulating lipoproteins in the blood.
C) decreasing the density of the lipoprotein.
D) conferring specificity for recognition by receptors on cells.

Question 38

Lp(a) is a genetic variant of _____; its presence _____ a genetic predisposition to heart disease.

A) LDL, increases
B) HDL, decreases
C) LDL, decreases
D) HDL, increases

Question 39

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 40

Trans unsaturated fatty acids are now considered more atherogenic than saturated fatty acids because they

A) are unnatural and only formed during fat processing.
B) cause excess blood clotting.
C) elevate serum LDL while decreasing HDL.
D) were found to cause sudden cardiac arrest in women.

Question 41

The fatty acid structure below is an omega-_____ fatty acid called _____. CH₃CH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₇COOH

A) 3, linolenic
B) 6, linoleic
C) 6, eicosapentaenoic
D) 9, oleic

Question 42

Which group of 20-carbon fatty acid derivatives can exhibit either pro-arrhythmic or anti-arrhythmic physiological actions in the body?

A) prostaglandins
B) thromboxanes
C) leukotrienes
D) sterols

Question 43

Which hormone is considered to be an antagonist of lipolysis?

A) insulin
B) epinephrine
C) glucagon
D) thyroxine

Question 44

A high rate of ethanol ingestion causes an _____.

A) increase in gluconeogenesis
B) increase in fatty acid synthesis
C) increase in protein breakdown
D) increase in glycogen synthesis

Question 45

Which of these enzymes is the primary system for oxidizing alcohol after 1 drink?

A) catalase
B) microsomal ethanol oxidizing enzyme
C) alcohol dehydrogenase
D) aldehyde carboxylase

Question 46

Thromboxane A₂ is a hormone-like substance made from:

A) stearic acid.
B) arachidonic acid.
C) palmitic acid.
D) myristic acid.

Question 47

Ketones are produced from:

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

Question 48

Thromboxanes that activate blood platelets are _____. When EPA is used to synthesize the thromboxane, it is _____.

A) vasodilators, a vasoconstrictor
B) pro-aggregatory, less pro-aggregatory
C) anti-inflammatory, pro-inflammatory
D) pro-aggregatory, anti-aggregatory

Question 49

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

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

Question 50

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) erucic acid

Question 51

During starvation, or when following a very-low-carbohydrate diet, the consumption of alcohol may cause hypoglycemia. Which of the following is NOT a contributing factor?

A) Alcohol breakdown depletes NADPH.
B) Alcohol breakdown favors the reduction of DHAP to glycerol-3-phosphate.
C) Alcohol breakdown diminishes formation of alpha-ketoglutarate.
D) Alcohol breakdown creates a high NADH:NAD ratio.

Question 52

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 53

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 54

Why might someone who is drunk have high blood lactate levels?

A) High levels of NADH produced by ADH shift the direction of the lactate dehydrogenase reaction.
B) High levels of NADH produced by the MEOS stimulate lactate dehydrogenase activity.
C) Consuming calorie-yielding compounds and not providing enough oxygen to cells increases anaerobic respiration.
D) Reducing equivalents inhibit the synthesis of lactic acid and increase the synthesis of acetaldehyde.

Question 55

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 56

What is considered the toxic level of blood ethanol?

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