NME 2.12

Question 1

describe digestion and absorption of lipids

Answer 1

• lipid emulsion
• allow pancreatic lipase to act on the lipid and digest it
• micelles get in beteen microvilli
• aggregated triglycerides form chylomicrons

Question 2

what are dietary lipid

Answer 2

• triester of glycerol and long chain fatty acid

- phospholipids

Question 3

what does the dietary lipid substitute?

Answer 3

• substitute 1 fatty chain with phosphor ester organic base

Question 4

which glycerol lipase cannot act on?

Answer 4

2nd glycerol

Question 5

what does co-lipase cleaves and cause?

Answer 5

• 1 and 3 linkages
• remove 2 fatty acid and 2 mono-glyceride
• isomerisation of 2 monoglyceride to 1 monoglyceride

Question 6

what causes the isomerisation of 2 monoglyceride?

Answer 6

• fatty acid on one part of teh glyceride will flip

Question 7

what does polar groups of bile salts impart on micelles?

Answer 7

• negative charge on the surface

Question 8

what does negative charges on micelles do?

Answer 8

• keep stable suspension

- mutual repulsion between micelles

Question 9

how does the composition of micelles changes down the small intestine

Answer 9

• content of fatty acid and monoacylglycerol diminishes while their proportional content of bile acid increases

Question 10

what deos the micelles have to diffuse across?

Answer 10

• unstirred layer to the enterocyte cell membrane

Question 11

what kind of micelles carry lipids through acidic unstirred layer?

Answer 11

• mixed micelles

Question 12

what leaves the mixed micelles and enter acidic microenvironment?

Answer 12

• 2-MAG
• fatty acid
• lysophospholipids
• cholestrol

Question 13

how does lipid enter enterocyte?

Answer 13

• nonionic diffusion
• incorporation into enterocyte membrane through collision
• carrier mediated transport

Question 14

which process of lipid digestion and absorption is rate limiting?

Answer 14

• lipid uptake

Question 15

what causes the acidic microclimate?

Answer 15

• proton exchanger

Question 16

how to make lipid easier to absorb?

Answer 16

• protonated which make it not charged and easier to absorbed

Question 17

what aids transport of cholestrol during absorption?

Answer 17

• neimann-pick C1 like-1

Question 18

what helps with absorption of fatty acid?

Answer 18

• fatty acid translocase

- fatty acid transport protein subtype 4

Question 19

what drives lipid uptake?

Answer 19

• re-esterification of fatty acid

Question 20

what does triglyceride resynthesis do?

Answer 20

• maintain diffusion gradient
• re-esterification of long chain fatty acids
• triglycerides transferred to chylomicrons and VLDL
• short and medium fatty acid go to portal circulation binding on albumin

Question 21

where in the cell does triglyceride re-synthesis occurs?

Answer 21

smooth endoplasmic reticulum

Question 22

where does the chylomicrons go?

Answer 22

• lacteals which will bypass the liver

Question 23

how is phospholipid synthesized by?

Answer 23

• esterification of lysophospholipid with fatty acyl-S-CoA

Question 24

how is cholesterol synthesized by?

Answer 24

• free cholesterol and fatty acyl-S-CoA

Question 25

what happens during lipid malabsorption?

Answer 25

• fatty stools

Question 26

what causes lipid malabsorption?

Answer 26

• pancreatic deficiency
• bile acid deficiency
• chylomicrons formation deficiency
• lymphatic deficiency
• drugs which interfere with lipid absorption