Degradation of dietary lipids

Question 1

why are Triacylglycerides the major fat in human diet

Answer 1

they are major storage lipid in plants and animals

Question 2

where does the majority of triacylglyceride digestion take place

Answer 2

lumen of intestine

Question 3

bile salts are what kind of compound

Answer 3

amphipathic

Question 4

secretion of gallbladder and pancreatic enzymes are stimulated by

Answer 4

CCK

Question 5

what happens to dietary fat in SI

Answer 5

emulsified by bile salts

Question 6

what is the major enzyme to digest Triacylglycerides

Answer 6

pancreatic lipase

Question 7

pancreatic lipase is secreted in response to

Answer 7

CCK

Question 8

what is secreted along with pancreatic lipase

Answer 8

colipase

Question 9

how does pancreatic lipase work against Triacylglycerides

Answer 9

cleaves ester bonds at each end to create 2 free FA & 2 monoacylglycerol

Question 10

what is colipase function

Answer 10

holds Pancreatic Lipase at interface between lipid & aqueous medium;

• this causes conformation change in lipase & exposes active site;
• requires activation by proteolytic chymotrypsin

Question 11

colipase requires activation via

Answer 11

proteolyic chymotrypsin

Question 12

orlistat is a drug that does what

Answer 12

fights obesity by inhibiting gastric & pancreatic lipases

Question 13

name two pancreatic neutral pH lipid-hydrolases in intestine

Answer 13

Cholesterol esterase

Phospholipase A2

Question 14

what is product after cholesterol esterase acts on choesterol ester

Answer 14

cholesterol

Question 15

what is product after phospholipase A2 acts on phospholipid

Answer 15

lysophospholipid

Question 16

after phospholipase A2 acts on phospholipid, what then removes remaining fatty acyl?

Answer 16

lysophospholipase

Question 17

what is another name for lysophospholipid

Answer 17

lysolecithin

Question 18

what does CCK do

Answer 18

gall bladder to release bile
release pancreatic enzymes
slows gatric contractions

Question 19

what does secretin do

Answer 19

promotes release of HCO3-

Question 20

what does steatorrhea mean

Answer 20

lipid malabsorption - fat in stool

Question 21

TAGs, cholesterol, and phospholipids combine into what

Answer 21

chylomicrons (CM)

Question 22

what happens to LCFA & cholesterol when they are absorbed

Answer 22

esterified

Question 23

how are TAG and cholesterol esters packaged

Answer 23

particles of lipid droplet

sourrounded by phospholipids, nonesterified cholesterol, apolipoprotein

Question 24

are short and medium chain fatty acids esterified

Answer 24

no

Question 25

why aren't short and medium chain fatty acids esterified

Answer 25

they are small enough to enter portal circulation directly, bind to albumin to be brought to liver

Question 26

what happens once short and medium chain fatty acids enter portal circulation

Answer 26

bind to albumin and brought to liver

Question 27

one albumin can bind how many FFA

Answer 27

up to 10

Question 28

intestinal mucosa assembles and secretes

Answer 28

chylomicrons

Question 29

chylomicrons are the sole

Answer 29

lipoprotein carrier of dietary lipid

Question 30

what is the sole lipoprotein carrier of dietary lipid

Answer 30

chylomicron

Question 31

draw out B-apoprotein gene being transcribed and translated

Answer 31

pg 14

Question 32

in liver the B-apoprotein gene is transcribed into

Answer 32

ApoB-110 gene

Question 33

how many AA in ApoB-110 gene

Answer 33

4536

Question 34

in intestine what happens to B-apoprotein gene

Answer 34

RNA editting, creating a stop codon and a smaller product

Question 35

what editting happens to B-apoprotein gene in intesting

Answer 35

C→U (stop codon)

Question 36

what is the resulting protein of intesting modification of B-apoprotein

Answer 36

ApoB -48

Question 37

how many AA in ApoB-48

Answer 37

2152

Question 38

in ApoB 48 chylomicron assembly with dietary lipid, what else is required

Answer 38

MTP

Question 39

what does MTP stand for

Answer 39

Microsomal (ER) Triglyceride Transfer Protein.

Question 40

what does MTP do

Answer 40

mediates process of Apo48 binding to lipid

Question 41

MTP deficiency causes

Answer 41

abetalipoproteinemia. LDM levels low and chylomicrons low. have problem with fat

Question 42

what is the consequence of MTP deficiency

Answer 42

lipid deficiency

Question 43

what is abetalipoproteinemia

Answer 43

defective assembly of all Apo-B bearing lipoproteins (CM, VLDL, IDL & LDL)

Question 44

what are the two major roles of chylomicron in blood

Answer 44

separate fats from H20 | signal tissue/cell

Question 45

what does chylomicron signal in blood

Answer 45

that a new meal has arrived

Question 46

ApoCII activates

Answer 46

LPL & ApoE

Question 47

chylomicrons are emptied out by

Answer 47

lipoprotein lipase

Question 48

lipoprotein lipase is indirectly activated by

Answer 48

insulin

Question 49

in blood, where is lipoprotein lipase kept?

Answer 49

it is held to inner capillary wall

Question 50

what anchors LPL to capillary wall

Answer 50

GPI

Question 51

what does GPI stand for

Answer 51

glycosylated phosphatidyl-inositol

Question 52

what helps keep LPL in lumen

Answer 52

SO4

Question 53

what is "leash" - what connects LPL to GPI to anchor to capillary wall

Answer 53

heparan sulfate's ionizable group

Question 54

if there is LPL deficiency what is observed

Answer 54

HUGE amount of fat in blood

Question 55

describe differnet tissue response to LPL

Answer 55

different tissues have different Km for LPL to meet the energy needs. Heart and muscle have low Km (so high affinity) b/c they need to obtain FA from LP's.

Question 56

what are remnants of chylomicron

Answer 56

cholesterol ester, phospholipid, Apo B-48 & E, fat-soluble vitamins (esp important); very little TAGs; cholesterol & nitrogenous glycerophospholipids (eg choline, serine) recycled

Question 57

if there is defective chylomicron remnant removal, what is disease

Answer 57

type III hyperlipoproteinemia aka familial dysbetalipoproteinemia

Question 58

what bond can we not digest in plants

Answer 58

ß 1,4 glycosidic bonds in polysaccharide plant wall

Question 59

we don't have enzymes to break what bond in plants

Answer 59

ß 1,4 glycosidic bond

Question 60

phosphatidylcholine has what kind of bonds

Answer 60

ester

Question 61

what does pancreatic lipase do

Answer 61

breaks triacylgylcerol into 2 monoacylglycerol

Question 62

bile acids are produced in liver from cholesterol and they are

Answer 62

Amphiphobic

Question 63

cholesterol on its own is very

Answer 63

hydrophobic

Question 64

acinar cells produce what

Answer 64

digestive enzymes

Question 65

pts with cystic fibrosis need to take pill to help

Answer 65

digesting food

Question 66

bile acids are derived from

Answer 66

cholesterol

Question 67

describe structure of micelle

Answer 67

hydrophilic outside hydrophobic component inside

Question 68

if pancreatic lipase is inhibited you inhibit

Answer 68

inhibit absorption of fat

Question 69

did orlistat work

Answer 69

no.

Question 70

gycerophospholipid

Answer 70

component of lipid of bilayer - amphiatic molecule | we get this when we eat animal

Question 71

CCK does what to gastrin

Answer 71

stops secretion of gastrin

Question 72

how can you get steatorrhea

Answer 72

problems in gall bladder, like stone gall bladder removed pancreas not secreting enzymes to lumen of intestine

Question 73

problem with CFTR is what disease

Answer 73

cystic fibrosis

Question 74

what causes problem with CFTR

Answer 74

deletion which inactivates protein | deletion of one aa causes inactivation of protein b/c it has huge AA

Question 75

on lumen side of cell chloride is exchanged for

Answer 75

bicarbonate

Question 76

if you don't have chloride then what happens in ductal cell (like in cystic fibrosis)

Answer 76

don't have bicarbonate leaving and have problems with pH so digestive enzmes won't work problems with water.

Question 77

pts with cystic fibrosis do not have what functional cell

Answer 77

acinar

Question 78

pancreatitis

Answer 78

digestive enzymes stuck in ducks. the enzymes contain proteases which will digest things. (he said it is another component of cystic fibrosis)

Question 79

ApoB100 is

Answer 79

VLDL

Question 80

VLDL

Answer 80

very low density lipoprotein

Question 81

when C is deaminated it produces

Answer 81

uracil

Question 82

chylomicrons and VLDL contain different proteins but they come

Answer 82

from the same gene

Question 83

MTP is internalized in

Answer 83

lipid

Question 84

the large ApoB particle will go where for maturation and secretion

Answer 84

golgi

Question 85

HDL is

Answer 85

cholesterol containing lipoprotein

Question 86

the higher HDL is that good or bad

Answer 86

the better it is. related to reduce cardiovascular disease

Question 87

review the concept map at end

Answer 87

pg 21