Fat Transportation Flashcards
Fatty acids and glycerol are further broken down into what?
Fatty acids into Acetyl CoA and glycerol used for gluconeogenesis.
Where is the majority of ATP synthesised and why?
The mitochondria as the formation of acetyl CoA forms ATP and acetyl CoA is produced from both types of major food molecules, fats and sugars.
In addition to this, oxidative phosphorylation from the reduced NADH, FADH2 also produce a lot of ATP
Where are the 3 main sources of fat?
The diet
De novo biosynthesis (liver)
Storage depots in adipose
A lack of bile salts results in what?
The majority of fat passing through the gut undigested and unabsorbed, resulting in steatorrhea (fatty stool).
Where are bile salts generated and stored?
Formed from cholesterol in the liver, stored in the gall bladder.
How do bile salts aid in the digestion of fats?
They pass from the bile duct into the intestine where they emulsify the fats, helping the body to break them down and absorb them and also the fat soluble vitamins (A,D,E,K)
What is orlistat (tetrahydrolipstatin)?
A potent inhibitor of gastric and pancreatic lipases and so a powerful fat loss treatment (reduces fat absorption by 30%, works for up to 2 years)
What are the 4 main side effects of orlistat?
Abdominal pain, urgency to defecate, increased flatus and steatorrhea.
How are lipids transported around the body?
Lipoproteins such as : CM (Chylomicrons), VLDL (Very Low Density Lipoproteins), IDL (Intermediate Density Lipoproteins), LDL (Low Density Lipoproteins), HDL (High Density Lipoproteins)
What are digested dietary products absorbed by?
Enterocytes that line the brush border of the small intestine.
What must happen before triglycerides absorbed are incorporated into chylomicrons?
Triglycerides must be resynthesized under the control of several enzymes.
What happens to CMs after incorporating triglycerides?
They are transported via the lymphatic and on into the bloodstream. They acquire apoproteins from HDL following release into the bloodstream.
How do CMs enter the bloodstream?
Travel from the lacteals of the small intestine to the thoracic duct and to the left subclavian vein where they enter the bloodstream.
How do the apoproteins allow the nutrients in a CM to enter cells?
Apoproteins bind to lipoprotein lipase receptors on the capillary endothelial cells which line a variety of tissues including adipose, heart and skeletal muscles.
What happens to the fatty acids and glycerol once in a cell?
Fatty acids undergo beta-oxidation to form Acetyl CoA.
Glycerol returned to liver for use in gluconeogenesis.
