Absorption Of Fat

cgeorge's version from 2016-02-24 13:22


Question Answer
Fats can be stored in a ....stateAnhydrous
Lots of visceral fat means you have what shape body?Apple
Lots of subcutaneous fat means you have what shape bodyPear
Process of beta oxidation isFatty acid chains are liberated from fats via lipases. These fatty acids go into B-oxidation. 2 oxidation steps, 2 ATP generated. Final step is to cleave 2 carbons from fatty acid chains, these 2 carbons make up acetyl coa which goes into krebs cycle to generate more ATP
The fat soluble vitamins areA,D,E and K
Vitamin A deficiency can cause Night blindness,corneal degeneration
Problem with overdosing on vitamin ACant be excrted very easily (not water solube.) So becomes stored within fat. Can lead to blurry vision/vomiting
Dietary vitamin is Vitamin D3
To change dietary vitamin D into an active form what needs to occur?2 hydroxylation reactions. First step occurs in liver, second in kidney
Sunlight can change 7-dehydrocholesterol into Vitamin D3
Vitamin E deficiency can result in Neurological problems due to poor nerve conduction
Which vitamin is involved in carboxylation of glutamate residues to form Gla-residuesVitamin K
Fats are an essential part of the diet becauseFats cant be derived endogenously
Triglycerides are made up ofLong chain fatty acyl esters of glycerol
95% of dietary lipids isTriglycerides
5% of dietary lipids arePhospholipids
Less than 5% of the diet is Cholesterol
Endogenous lipids in the GI lumen are predominantly from bile which contains 4 things;1) Phospholipids 2) Unesterified cholesterol 3)Membrane lipids from desquamated cells 4) Lipids derivded from dead colonic bacteria
Lipid hydrolysis occurs in the ... of the intestinal lumenAqueous milieu
Dietary lipids are stabilised as an emulsion in theMouth/stomach by chewing/squirting of gastric contents into the duodenum
What prevents the lipid particles from coalescin?Within the fat droplet theres phospholipids with polar hydrophilic head groups. If 2 polar heads come together they repel
Lingual and gastric lipase break down ... into ... + ....Triglyceride > Diglyceride + 1 fatty acid chain
Are long chain fatty acids absorbed in stomach?No, they are insoluble @ acidic PH, they remain in the core of the triglyceride droplet
Are medium/short chain fatty acids absorbed in the stomach?Yes, they are mainly ionized at gastric PH, so passively absorbed across the mucosa into portal blood
CCK stimulates 2 things;1) Contraction of gall bladder 2) Relaxation of sphincter of Oddi
Pancreatic lipase requires 4 things to be activated;1) Colipase 2) Alkaline PH 3) Bile salts 4) Fatty acids
Pro colipase requires what enzyme to convert it into colipase?Trypsin
What are the products of pancreatic lipase?Fatty acid chains and 2-monoacylglyceride
How do multilamellar vesicles form from the multilamellar lipid droplet when lipases act on it?Lipases anchor onto the emulsion droplet. As the core lipid is digested, the core droplet is getting smaller. As the lipid within the droplet takes up a smaller space, the droplet starts to pinch off > multilamellar vesicles
How do fatty acid/bile salt mixed micelles get into the enterocyte?When they reach enterocyte surface, they encounter a low PH generated by the Na/H exchanger at the brush border membrane. The fatty acids are protonated and leave the mixed micelles > enter enterocyte
What happens to the long fatty acid chains inside the enterocyte?Bind to fatty acid binding protein, reesterified (made back into a fat droplet), then complexed with apoproteins. Chylomicrones then traffic to the golgi
What are chylomicronesApoproteins associated with fat droplets