Lipid Metabolism

Question 1

What is the role of fatty acid oxidation

Answer 1

responsible for providing energy to cells when glucose is low

Question 2

excess ______ is converted to fatty acids that can be stored or exported as triaglycerols

Answer 2

acetyl-CoA

Question 3

What is ketogenesis

Answer 3

production of ketone bodies by the breakdown of fatty acids and ketogenic amino acids

Question 4

ketogenesis supplies energy to certain organs (particulairly the brain) under what circumstances

Answer 4

starvation or fasting

Question 5

Most humans have enough triacylglycerols in adipose to last __ months in starvation

Answer 5

3

Question 6

what are the key enzymes in fatty acid oxidation and synthesis

Answer 6

fatty acyl-CoA synthease, carnitine acetyltransferase I, acetyl-CoA carboxylase, fatty acid synthase

Question 7

what does fatty acyl-CoA synthease do

Answer 7

catalyzes “priming” reaction in metabolism

Question 8

what does carnitine acetyletransferase I do

Answer 8

catalyzes the commitment step in oxidation

Question 9

what does acteyl-CoA carboxylase do

Answer 9

catalyzes the commitment step in synthesis

Question 10

What does fatty acid synthase do

Answer 10

catalyzes a series of reactions that adds C2 units to a growing fatty acid chain

Question 11

the carnitine transport cycle translocates ____ ___ across the inner mitochrondrial membrnae

Answer 11

fatty acids

Question 12

The complete oxidation of palmitoyl-CoA requires ____ cycles of the __ step beta cycle to yield _acetyl-CoA, _FADH2 and _NADH

Answer 12

requires seven cycles of the four step beta cycle to yield 8acetyl-CoA, 7FADH2 and 7NADH

Question 13

Ketogenesis slavages _____ from liver mitochondria and converts it to _____ and _____

Answer 13

acetyl-CoA and converts it to aceoacetate and D-beta hydroxybutyrate

Question 14

ketone bodies in the liver are exported to the ____

Answer 14

blood

Question 15

oxaloacetate is used to make ______ for gluconeogenic pathway, therefore increasing acetyl-CoA lelvels

Answer 15

phophophenol pyruvate

Question 16

What are the four steps inthe fatty acid synthase complex

Answer 16

condensation, reduction, dehydration, reduction

Question 17

What are the two cycles in the fatty acid sythase compolex

Answer 17

1. priming reaction where acetyl group attaches to sulfhydryl group of a Cys residue
2. malonyl group from malonyl-CoA attached to ACP by MAT subunit

Question 18

what are the three biochemical reactions that control the flux of fatty acid synthesis and degredation

Answer 18

1-citrate activation of acteyl-CoA carboxylase
2-inhibition of canitine acyltransferase by malonyl-CoA
3-inhibition of acetyl-CoA carboxylase by fatty acyl-CoA

Question 19

cholesterol is an essential lipid constituant for _______

Answer 19

cell membranes

Question 20

cholesterol is a precursor of ____ hormones and of ___ ___

Answer 20

steroid hormones and bile acids

Question 21

high plasma cholesterol promotes ___________

Answer 21

artherosclerosis

Question 22

lipoprotein particles contain what?

Answer 22

cholesterol ester, tricylglycerols

Question 23

when do artheroscleroic plaques form

Answer 23

when injury occurs to the endothelial lining, allowing LDL particles to invade and initiate an immune response

Question 24

what are artheroscleroic plaques made up of

Answer 24

cholesterol and fat deposits, microphage foam cells and fibrous material

Question 25

What are statin drugs

Answer 25

HMG-CoA reductase inhibitors that lower serum LDL levels

Question 26

What is Ezetimbe

Answer 26

blocks the import of dietary cholesterold by inhibiting the transport of NPC1L1 protein from small intestine

Question 27

Bile acid binding resins are used for what?

Answer 27

to lower serum cholesterol levels

Question 28

where does beta oxidation of fatty acids occur

Answer 28

in the mitochondrial matrix

Question 29

what are the four cyclic reactions in beta oxidation of fatty acids

Answer 29

dehydration, hydration, oxidation and thyolysis

Question 30

what happens in each cycle of beta oxidation

Answer 30

a fatty acid is progressively shorted by 2 carbons as its oxidized and energy is captured by NADH and FADH2

Question 31

at the end of each beta oxidation cycle what is your product

Answer 31

acetyl-CoA

Question 32

if an odd number of carbons are left what is your product of beta oxidation cycle

Answer 32

propoionyl-CoA

Question 33

What is the ATP yeild of palmitoyl CoA per NADH and FADH2

Answer 33

2.5ATP per NADH, 1.5 ATP per FADH2

Question 34

What is the overall ATP yeild per palmitoyl CoA

Answer 34

108 ATP