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38 Cards in this Set
- Front
- Back
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what happens to the FA not absorbed in the lumen? |
become calcium salts (FA generally palmitate or stearate) plus calcium
FAA must be in Sn2 in order for this to happen |
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main areas chylomicrons deliver FA's to? |
adipocytes, mammary glands, muscle cells |
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what happens to 2-monoglycerol? |
further hydrolysed at liver surface or taken up as chylomicron remnant |
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what is the source of FFA in the plasma? |
adipocytes especially around abdomen |
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why is increased abdominal fat a health risk |
more likley to be oxidised |
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name the apolipoproteins associated with each lipoprotein |
HDL- apoA1 LDL/VLDL - apo100 chylomicron - apoB48 |
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what is the least dense lipoprotein? |
chylomicron |
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what is hypercholesterolaemia? |
high LDL due to either modifiable or non modifiable factors (e.g. faulty LDL receptors) |
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what is the reaction for cholesterol synth, what is the rate limiting step? |
acetyl CoA ---> HMG CoA ---> mevalonate -------> cholesterol
HMGCoA rate limiting |
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how does a cell increase uptake of LDL to lower plasma levels? |
increase transporter activity/ numbers
increase BA and cholesterol prod by decreasing reabsorption |
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what factors influence the transporter numbers and activity? |
gene expression (low chol conc = increased gene expression) - long term
fluidity of membranes- infl by FA in phospholipids that make up the membrane- infl by diet |
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how does HDL collect cholesterol? |
interacts with ABCA1 and collects excess cellular cholesterol, takes it back to liver via exchange with other lipoproteins |
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whats good about fermentable/ soluble fibre? |
bacteria get ATP, SCFA produced, decreases reabsorption of BA and chol, increase bacteria content in faeces, indirectly increasing water content |
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what does it mean to conjugate a bile acid and what is it purpose? |
conjuagte = formind amide bond b/w carboxyl group and amide gp
makes a better emulsifying agent |
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3 things dietary FA's used for? |
storage, E source, part of membranes |
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what functions do both ALA and LA share? |
E substrates B oxidation stored as TG substrates for desat/ elong enzymes into VLCPUFA |
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whats different about LA? |
component of membranes, lipoproteins and skin ceramides |
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is coconut oil a good source of EFA's? |
no coconut oil contained lauric |
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which is the best oil to consume to give ALA best chance of conversion? |
canola has 1:2 ratio |
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LCPUFA are found in plasma membranes name 2 specific and where they are found |
DHA- light receptor cells in the eye AA- cerebral cortex, spleen |
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DHA significant function in eye and cerebral cortex |
fluidity and neurotramission of membrane, allows more lateral movement |
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eicosanoids are made up of 20PUFA how? where does the substrate supply come from? |
from plasma membranes released by phospholipase A2 |
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type of eicosanoid produced depends on the tissue, elaborate |
prostaglandins - macrophage leukotrienes - neutraphils thromboxanes - platelets |
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what is the purpose of eicosanoids? |
act locally (paracrine hormones) influence blood vessel activity, inflammatory responses, platelet aggregation |
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how do phytosterols decrease plasma chol conc? |
compete with cholesterol for place in micelle within enterocyte prevent chol being reseterified stim transporter which transfers chol back to lumen |
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what is dehydroxylation of BA? |
removing O2 forming secondary BA these can be conjugated and secreted |
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N isn't lost in protein synth in the body, is it lost in synth of non protein N containing compounds? |
depends
switching between amino acids- no (phenylalanine to tyrosine)
creatine to creatinine- yes (creatine needs to be synthesised to replace excreted creatinine) |
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what things affect protein synthesis? |
aa pool (limiting aa) ribosome concentration leucine; regulates and initiates translation |
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how is urea synthesised to accommodate an increase in protein intake? |
aminotransferase create glutamate glutamate + H2O = ammonium ammonium can be converted to urea and excreted |
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some urea is transferred to the colon, explain how this works |
1/3 is reabsorbed into colon hydrolysed by bacteria to NH3 some NH3 used to make aa for bacteria some NH3 reabsorbed, taken to liver and author converted back to urea or used for aa synth |
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where is urea reabsorbed from? |
descending tubules |
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how do you calculate: the amount of urea lost in urine amount of urea recycled the amount lost from excretion if in 20 g positive N balance (building muscle) |
urine loss = 90% (multiply intake by 0.90) the difference between this and the total is the amount lost through other means
divide by 3 (1/3 is recycled)
20 x 0.16 = 3.2 g N excreted N - 3.2 = 7.8g |
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3 sources of endogenous proteins? |
digestive enzymes secretions sloughed off cells |
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which milk protein digests slower? |
caesin, clots in stomach = satiety of milk and diff fates of aa |
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what do bacteria use N for? |
to make aa and to divide and multiply |
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transporter eg. for peptides? |
PEPT1 |
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BCAA go to muscle the rest go to the liver to be..... |
used for ptn synth synth of other N containing compounds catabolised |
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diff b/w protein and aa metabolism |
protein- catabolism/ anabolism ptns aa- using up aa by making creatine or other aa or used as E substrate / intake, synth of aa |
