Lipid Metabolism Revision

Question 1

lipoprotein lipase site and co factors required

Answer 1

vascular endothelium of extra hepatic tissue

requires apo c 11 and phospholipids

Question 2

lipoprotein lipase vs HSL vs pancreatic lipase

Answer 2

lipoprotein lipase- break TAG in blood (from chylomicron) for uptake during feeding
HSL- break TAG during fasting that is stored in adipose tissue for oxidation
pancreatic lipase- break TAG in cavity of intestine for digestion during feeding

Question 3

glycerol fate

Answer 3

can’t be utilized by adipose tissue due to deficiency of glycerol kinase so goes to liver and kidney

Question 4

key enzyme of lipolysis

Answer 4

HSL helped by MAG

Question 5

how do long chain fatty acids get to mitochondria

Answer 5

they from acyl coA which does in inner space of mitochondrial matrix then binds with carnitine to make acyl carnitine with CPT1 and goes to matrix by carnitine shuttle and in the matrix of the mitochondria, CPT2 separates acyl coA from the carnitine and the carnitine goes back to inner space.

Question 6

each cycle of FA oxidation will release

Answer 6

acetyl coA (enters krebbs after)
formation of one FADH2 and one NADH

Question 7

steps of beta oxidation

Answer 7

acyl coa – acyl CoA DH –> delta 2 trans enoyl coA –> beta hydroxyacyl coA –> b ketoacyl coA –> acetyl coA + new acyl coA (2 carbons less)

Question 8

calculate # of acetyl coA
# of cycles
complete oxidation of FA

Answer 8

# of carbon / 2
# of acetyl coA - 1
7C-6

Question 9

Importance of FA oxidation

Answer 9

1. supply body with energy in starvation

2. formation of acetyl coA

Question 10

malonyl coAA effect on b oxidation

Answer 10

produced during FA synthesis inhibits CPT 1

Question 11

How is FADH2 released from peroxisomal oxidation regenerated?

Answer 11

by giving its H2 to H2O2 to from 2 H2O and it doesn’t go to ETC

Question 12

refsum disease and symptoms

Answer 12

deficiency in a hydroxyls so accumulation of phytanic acid 
DBAP 
deafness
blindness
ataxia
polyneuropathy

Question 13

two systems for fatty acid synthesis

Answer 13

1. cytosolic de novo (lipogenesis)

2. microsomal system for elongation

Question 14

acetyl coA for FA synthesis comes from

Answer 14

carbohydrate metabolism

Question 15

site of cytosolic or de novo fatty acid synthesis vs microsomal

Answer 15

de novo: liver and lactating mammary gland and some in adipose tissue
microsomal: endoplasmic reticulum

Question 16

how is acetyl coA produced from TCA go to cytosol for de novo synthesis and what happens to oxaloacetate

Answer 16

through citrate shuttle
oxaloacetate is then turned to malate then to pyruvate by Malik enzyme which can go back to mitochondria .
you can convert oxaloacetate straight to pyruvate if you don’t need NADPH+H

Question 17

FA synthesis enzymes

Answer 17

ACC- acetyl coA -> malonyl CoA

FAS- multi enzyme complex (7 enzymes and have acetyl carrier protein)

Question 18

product of FA synthesis

Answer 18

palmitic acid

Question 19

microsomal system differs from denote in 3 aspects

Answer 19

1. can’t imitate, just elongate from 10-24
2. enzymes are separate
3. no ACP

Question 20

glycerol 3 phosphate in adipose tissue

Answer 20

no glycerokinase in adipose tissue (only liver and kidney) so produced by glucose by turning it into DHAB.

Question 21

tissue fat vs depot fat
site
function
composition
amount and effect on diet

Answer 21

tissue- every cell, enter in structural elements and not used for energy. made up of phospholipids, glycolipids and cholesterol. constant and not affected by diet.

depot fat- adipose tissue and for energy storage, TAG and increases by overeating and decreases by fasting

Question 22

tissue fat or depot fat?

which is rich in saturated and unsaturated fatty acids?

Answer 22

tissue fat- unsaturated fatty acids

depot fat- saturated fatty acids

Question 23

how are cyclic compounds formed?

Answer 23

from prostaglandin H synthase which has 2 activates: COX and peroxidase

Question 24

COX 1 vs COX 2

Answer 24

cox 1 - enzyme found in most tissues

cox 2- enzyme that is generated due to response to inflammation

Question 25

acrylic compounds: how are they formed and ex?

Answer 25

formed by action of lypoxygenase and leukotrienes and lipoxins

Question 26

functions of eicosonaoids

PGE2 and PGE2 alpha site and functions

Answer 26

both are in most tissues.
PGE2- vasodilation, muscle relaxation, relieves asthma. does antiflammatory reactions to protect body such as pain, fever, and vasodilation.

PGE2 alpha- vasoconstrictor, muscle contraction, causes bronchoconstriction, used in induction of labor

Question 27

PGI2 and TXA2 Site and function

Answer 27

PGI2- Endothelium of blood vessels
does vasodilation and inhibits

TXA2 - platelets
does vasoconstriction and activates lately aggregation

Question 28

leukotrienes and lipoxins site and functions

Answer 28

leukotries- platelet, mast cells, leukocytes
stimulate migration of neutrophils (chemotaxis) for polymorphonuclear infiltration in inflammatory reactions. It also does allergic reactions

lipoxins - arterial walls and anti inflammatory and decrease immune response

Question 29

steroidal anti inflammatory drugs inhibit: and ex

Answer 29

ex: hydrocortisone, prednisone, betamethasone
NO COX, NO LOX

phospholipase A2 so less availability of arachidonic acid

Question 30

non steroidal anti inflammatory drugs (NSAID) inhibit and ex

Answer 30

inhibit COX

aspirin: inhibit COX 1 more than COX 2 = bad
other: inhibit both equally such as ibuprofen and indomethacin

Question 31

singular

Answer 31

inhibits LOX so relieves bronchospasm and allergic reactions