Chapter 16- Imi Biochem

Question 1

function of lipids

Answer 1

Thermal insulation Energy storage (as TG) Metabolic fuels Membrane components (Phospholipids & cholesterol) Hormones (steroids & vitamin D) Precursors of prostanoids & Leukotriens Vitamin A, D, E, & K Emulsifying agents in the digestion & absorption of lipids (bile acids) Surfactants in the alveolar membrane (phosphatidylcholine)

Question 2

Non-polar lipids

Answer 2

triacylglycerols, cholesteryl esters

Question 3

Polar lipids

Answer 3

Fatty acids, cholesterol, glycerophosphatides, glycosphingolipids

Question 4

lauric acid carbons

Answer 4

12, produces net 95 ATP

Question 5

myristic acid carbons

Answer 5

14, produces net 112 ATP

Question 6

palmitic acid carbons

Answer 6

16, produces net 129 ATP

Question 7

stearic acid carbons

Answer 7

18, produces net 146 ATP

Question 8

arachidic acid carbons

Answer 8

20, produces net 163 ATP

Question 9

oleic acid

Answer 9

18 carbons 1 double bond, produces net 144 ATP

Question 10

linoleic acid

Answer 10

18 carbons 2 double bonds

Question 11

arachidonic acid

Answer 11

omega 6, 20 carbons and 4 double bonds, produces net 155 ATP

Question 12

increased FA oxidation characteristic of

Answer 12

starvation and DM producing ketone body production in the liver

Question 13

during starvation what cycle is inhibited

Answer 13

TCA

Question 14

3 acyl-CoA synthases

Answer 14

acetyl-CoA synthase medium-chain acyl-CoA synthase acyl-CoA synthase

Question 15

how is acyl-CoA is transported into the mitochondrial matrix

Answer 15

acyl-CoA-synthase -> carnitine palmitoyl transferase I -> carnitine acylcarnitine translocate -> carnitine palmitoyl transferase II

Question 16

Inhibitor of carnitine palmitoyl transferase I

Answer 16

Malonyl-CoA, a precursor in the synthesis of FAs, is an allosteric inhibitor of CPTI in the liver

Question 17

Malonyl-CoA prevents what

Answer 17

futile cycle of simultaneous FA oxidation & synthesis

Question 18

carnitine is synthesized from

Answer 18

Lys & Met

Question 19

inherited defects of carnitine metabolism results in

Answer 19

impaired utilization of long chain fatty acid metabolism, hypoketotic hypoglycemia

Question 20

beta-oxidation occurs in

Answer 20

mitochondria

Question 21

defects in FA oxidation

Answer 21

mitochondrial electron transfer flavoprotein and ETF-ubiquinone oxidoreductase, turns in beta-oxidation spiral, activation to CoA derivatives carnitine mediated translocation into mitochondria

Question 22

beta oxidation energetics palmitic acid

Answer 22

C16, 8 reactions x12 = 96, 7 FADH2 produced x2= 14, 7 NADH produced x3= 21, total ATP produced=131, net ATP 130 due to 1 ATP initial investment

Question 23

carnitine palmitoyl transferase 1 in inhibited by

Answer 23

malonyl-CoA

Question 24

acetyl-CoA carboxylase is inhibited by

Answer 24

glucagon

Question 25

acetyl-CoA carboxylase is stimulated by

Answer 25

insulin, acyl-CoA

Question 26

glucagon ultimately does what in fatty acid oxidation

Answer 26

stimulates fatty acid oxidation by inhibiting acetyl-CoA carboxylase that catalyzes malonyl-CoA formation

Question 27

insulin ultimately does what in fatty acid oxidation

Answer 27

inhibits fatty acid oxidation by stimulating acetyl-CoA carboxylase that catalyzes malonyl-CoA formation

Question 28

peroxisomal fatty acid oxidation occurs in

Answer 28

VLCFA, 20 carbons or longer

Question 29

preliminary peroxisomal FA oxidation

Answer 29

a preliminary β-oxidation in peroxisomes, shortened FA to octanyl-CoA and acetyl-CoA then transported to mitochondria for further oxidation

Question 30

how many ATP does peroxisomal oxidation yield

Answer 30

none, all energy produced appears as heat

Question 31

initial peroxisomal FA oxidation catalyzed by

Answer 31

flavoprotein dehydrogenase

Question 32

FADH2 produced by flavoprotein dehydrogenase in peroxisomal FA oxidation is

Answer 32

oxidized by O2 to H2O2 by cats

Question 33

zellweger's

Answer 33

defective formation of peroxisomes or enzymes resulting in accumulation of VLCFA in liver & CNS causing severe neurological symptoms, death

Question 34

neonatal adrenoleukodystrophy childhood adrenoleukodystrophy

Answer 34

abnormality in peroxisomal ATP-binding cassette transport membrane protein (ABCD1) for VLCFA causing accumulation of VLCFA in brain causing severe neurological symptoms, death

Question 35

product of odd-chain number FA oxidation

Answer 35

propionyl-CoA

Question 36

sources of propionyl-CoA

Answer 36

isoleucine, valine, methionine, threonine catabolism, or cholesterol side chain oxidation

Question 37

propionyl-CoA can be converted to

Answer 37

succinyl-CoA -> oxidized or converted to glucose by OAA and pyruvate or delta-ALA (precursor for porphyrin biosynthesis)

Question 38

formation of succinyl-CoA from propionyl requires

Answer 38

3 mitochondrial enzymes and 2 vitamins (biotin and B12)

Question 39

alpha oxidation involves

Answer 39

oxidation of LCFA to 2-OH FA's (catabolism of branched chain FA)

Question 40

oxidation of LCFA to 2-OH FA's are constituents of

Answer 40

brain lipids

Question 41

Refsum's disease

Answer 41

deficiency of phytanoyl-CoA hydroxylase, a peroxisome phytanic acid storage disease, defect of α-oxidation

Question 42

Phytanic acid derived from

Answer 42

animal fat and cow's milk, from chlorophyll

Question 43

Refsum's disease characterized by

Answer 43

accumulation of phytanic acid

Question 44

symptoms of Refsum's

Answer 44

retinitis pigmentosa, failing night vision, peripheral neuropathy, cerebellar ataxia

Question 45

ω-Oxidation

Answer 45

Oxidation of the C atom most remote from the carboxyl group in a FA

Question 46

ω-Oxidation catalyzed by

Answer 46

monooxygenase that require NADPH, O2, & cyt P-450

Question 47

ω-Oxidation occurs in

Answer 47

liver microsomes & some bacteria

Question 48

ω-Oxidation produce

Answer 48

dicarboxylic acids that are further oxidized from either end

Question 49

oxidation of mon and poly unsaturated FA's produced how many ATP per double bond

Answer 49

2

Question 50

linoleum acid

Answer 50

omega-6

Question 51

linolitic acid

Answer 51

omega-3