Fatty Acids Flashcards

Question

Cholecytokinin (CCK)

Answer 1

Secreted from intestinal mucosa in response to presence of lipids —> stimulates the gall bladder and pancreas to secrete their products

Answer 2

Secreted by gall bladder in presence of CCK

Answer 3

Pancreatic lipases Stimulated by CCK

Answer 4

1. Bile salts emulsify fats —> forming mixed MICELLES 2. TGs are degraded by the lipases to form fFAs and 2-monacylgylcerol 3. Lipid-soluble components (fat soluble vitamins etc) diffuse from the micelle into the mucosa of SI 4. FFAs converted back to TG 5. Mucosal cells package TGs, cholesterol and cholesteryl esters, phospholipids, and ApoB-48) into chylomicrons

Answer 5

Apolipoprotein complex that transports dietary TGs to the peripheral cells Outer layer = phospholipids, cholesterol, and apolipoproteins (polar groups face aqueous environment) TGs = >80% of mass of cm

Answer 6

1. CM is released into the lymphatic system 2. Then into bloodstream for delivery to peripheral cells 3. ApoC-II activates lipoprotein lipase 4. Converts TGs —> fFAs and glycerol 5. FFAs enter peripheral cells, where they are converted back to TGs for storage (adipose) or oxidized for energy (muscle)

Answer 7

Increase in lipids (especially FSVs and essential FAs) in the feces Caused by disturbance of lipid digestion and/or absorption E.g. cystic fibrosis can cause thickness in SI secretions and disrupts digestion Increasing short and medium FAs in the diet —> increase absorption rate of fat soluble vitamins and essential FAs

Answer 8

1. Glycerol-3P (G3P) formed 2. FA chain activated by Coenzyme A 3. First FA chain attached to C1 position of G3P by an ACYL TRANSFERASE 4. Process repeated to add a second carbon —> phosphatidic acid (PA) 5. Phosphate removed from by PA phosphatase —> 1,2-diacylglycerol (DAG) 6. Step 3 repeated to add third FA —> TGs

Answer 9

Intermediate in TG synthesis (after second FA is added) Can also be used in phospholipid synthesis

Answer 10

1. Reduction of DHAP — by G3P dehydrogenase (needs NADH) —intermediate from glycolysis 2. Phosphorylating glycerol —by glycerol kinase (needs ATP)

Answer 11

Only express G3P dehydrogenase...so can only do that pathway to make G3P to start TG synthesis Consequences for fasting state: Hydrolyze TG —> fFAs and glycerol —> which cannot be used later in the well-fed state Makes senses functionally because: 1. Fasting state —> inhibit reverse reaction of glycerol —> G3P...therefore FAs must leave the cell to be used elsewhere in the body for energy ... since TG synthesis has no backbone to add FAs to... 2. G3P will be generated when there is sufficient DHAP (well-fed) —> when TG storage is desirable

Answer 12

1. GPCR stimulated 2. Elicit a cAMP-dependent 2nd messenger 3. Stimulate PKA pathway 4. Phosphorylates hormone sensitive lipase and perilipin (to allow lipase to access the TGs in the fat droplets)

Answer 13

Protein that binds to fFAs to transport them in blood After they are released into blood from adipose after they are mobilized under glucagon/epi pathway

Answer 14

Go to the liver —> repackaged into TGs Exported to the perpheral cells or stored back in the adipocytes

Answer 15

Go to liver Fasting —> converted to glucose (gluconeogenesis) Well fed —> G3P by glycerol kinase for TG syn

Answer 16

High insulin Stimulates synthesis and secretion of lipoprotein lipase —> hydrolyzes circulating TGs in CMs —> allows peripheral access to fFAs Liver —> fFAs —> TGs —> exported to peripheral Adipose —> fFAs —> TGs Inhibits hydrolysis of preexisting TGs in adipose

Answer 17

More stimulated via glucagoon/epinephrine than by insulin Makes sense because... In a well fed state —> muscles can derive their energy from glucose and store than energy as glycogen...hydrolysis and utilization of fFAs for energy is less needed for skeletal muscles cells Cardiac muscle —> gets most of energy from TGs and will use both glucose and fFAs as energy sources for muscle contraction

Answer 18

Low insulin/high glucagon Muscle cells —> induce lipoprotein lipase to gain alternate fuel Adipose —> stimulated to hydrolyzes TGs, Liver —> produce glucose via gluconeo, use fFAs for energy, and also takes up fFAs in circulation —> TGs (to avoid too much fFAs in blood)