Molecular Fundamentals - Digestion and Absorption of Lipids

what are considered lipids?

• triglycerides

• cholesterol

• fatty acids

• phospholipids

lipids are insoluble in water, and therefore cannot do what?

circulate freely

how are lipids important to our body?

• structural component of the cell membrane

• help in providing energy and produce hormones

• healthy part of our diet if taken in proper amounts

what can our body not absorb?

polymers (such as triglyceride, cholesterol ester, phospholipids)

our body can only absorb what?

monomers (such as monoacylglycerol, free fatty acid, cholesterol, glycerol, phosphate) 

what does salivary and gastric lipase do?

• digest ester bonds

• break down triglycerides

triglyceride breaks down into what?

free fatty acid and MAG

salivary and gastric lipase digests what bond?

ester bonds

what is the cell in the stomach wall that releases gastric lipase to aid in digestion of lipids?

chief cells

what organ makes bile?

liver

what organ stores bile?

gall bladder

what does pancreatic lipase do?

degrade ester bonds in triglycerides and phospholipids

what is the protein co-enzyme required for optimal enzyme activity of pancreatic lipase?

colipase

bile/bile salt is released from where?

liver or gallbladder

bile salt is very important for what?

emulsification of lipid globule

bile salts help the lipid globule to do what?

enter the intestinal chyme

bile salts are used in emulsification to do what?

break fat lobule down into lipid droplets

lipid droplets contain what?

both polymers and monomers

after emulsification, lipid droplets are broken down into what?

micelles by colipase and lipase

micelles contain what?

only monomers

bile acids/salts are synthesized in where?

liver

bile acids/salts are secreted into the intestinal lumen via what?

gallbladder

micelle does what during fat absorption?

fuses with the enterocyte and contents get released into the enterocyte

after micelle fuses with enterocyte, what happens to the bile salts?

they are recycled back to the liver

what organelle converts the monomers back into polymers within the enterocyte?

smooth endoplasmic reticulum

to make bile salts, you need what?

cholesterol

what organelle packages and tags polymers with ApoB 48?

rough endoplasmic reticulum

what enzyme packages and helps tags polymers with ApoB 48?

MTP

chylomicron are only synthesized where?

in enterocytes

what describes chylomicron?

lipoportein that contains polymers and is tagged with ApoB 48

chylomicron uses what to enter the bloodstream due to its size? 

lacteals 

what is the function of the endoplasmic reticulum?

makes proteins and stores calcium