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Biochem 2 - PCC

Fat soluble vitamins

QuestionAnswer
What are the fat soluble vitamins? A D E K
How are they transported? In chylomicrons
Are they able to be stored? Yes, liver and adipose tissue
Are they toxic in large amounts? Yes
Oxidation of vitamin A 1. Retinol 2. Retinal 3. Retinoic acid
Retinol Reproduction and growth
Retinal Eyes, vision
Retenoic Acid Cell differentiation
Where can you find preformed vitamin A? In animal products and Retinol Esters (RA)
Where can you find proformed vitamin A? In plant products (red, orange, yellow)
What can be oxidized if your vitamin A content is too low? Retinal
Vitamin a deficiency leads to what? Vision problems but rare in developped nations
What happens if you take too much vitamin A ? (toxicity) 1. Can lead to defects in pregnant woman 2. Months of overconsuming caretenoids can lead to orange skin 3. Supplements of any kinds should not be taken by smokers
What are caretenoids and RE bound to in food? Fatty acid and protein
What strips the protein part from the vitamin A? Pepsin in the stomach and protease in the small intestin
What strips the fatty acid from the vitamin A? Prancreatic RE hydrolayse or esterase in the brush border
What is the role of bile in vitamin A? Makes it soluble
Where do the retinol and carotenoids incorporate themselves in order to be digested? In the micelles
How is vitamin A a brought into the duodemnum and jejunum? Through passive diffusion
Where is the retinol reesterified and by what? In the enterocytes by lecithin: retinol acyl transferase (LRAT)
In vitamin A absorption, what are the RE incorporated into? Chylomicrons
What happens if retinol intake is low? Carotenois are metabolized to 2 retinals: 1. Bound by CRBP, reduced to retinol, esterified via LRAT and incroporated into chylomicrons or 2. oxidized to retinoic acid and travels to the liver bound to albumin
What does vitamin D work with in order to regulate blood calcium? Parathyroid hormone
What is the name of active vitamin D? Calcitrol
What happens in relation to vitamin D when calcium is too low? 1. Increased absorption of calcium and phosphorus in small intestine 2. Decreases calcium excreation in kidneys 3. Removes calcium and phosphorus from bone to increase concentration in blood.
What is synthesized when blood calcium is low? Calcitrol
What does calcitrol affect? 1. Cell differentiation 2. Cell growth 3. Cell proliferation
What is topical calcitrol used for? Psoriasis
Why are obese patients sometimes lacking in vitamin D? Because adipose tissue acts as a sink for vitamin D.
Vitamin D deficientcy can lead to what? Rickets, type 1 diabetes, MS, RA and Crohn's disease
What type of digestion is associated with vitamin D? No digestion necessary
How is Vitamin D absorbed? It is incorporated into micells and absorbed via passive diffusion in the small intestine
How is vitamin D transported? 40% chylomicrons 60% is bound to vitamin D-binding protein (DBP) and transported into the blood
Where is vitamin D3 made? In the skin
Once vitamin D3 is bound to DBP where does it go? To the liver but it may be picjed up by muscle or adipose tissue before reaching the liver
What happens to vitamin D3 once it reaches the liver? It is hydroxylated and released back into the blood
What happens to the vitamin D that reaches the kidneys? It is hydroxylated again to form calcitrol
What are the functions of vitamin E? 1. Membrane integrity 2. Helps stop reactions involving free radicals 3. May decrease LDL oxidation
What is the diffrence between vitamin E supplement and dietary vitamin E? It is not nearly as active
What does large doses of vitamin E interfere with? Other fat soluble vitamins
Vitamin E transport hg
hgtrf htyf
Vitamin K functions 1. Blood clotting 2. Bone formation
What is vitamin k dependant on in relation to blood clotting and bone formation? Carboxylation of glutamic acid
What can alter the vitamin K pathway? Anticoagulants such as coumadin
Digestion of vitamin K No digestion necessary
How is vitamin K incorporated into the micelles? With the help of bile
Where is vitamin K abosorbed? 1. Small intestine 2. Ileum 3. Colon
How is vitamin K transported? It is packaged in chylomicrons
Vitamin A deficientcy leads to what? 1. Vision problems 2. Decrease immune function
Excess vitamin A can cause what? 1. Birth defects 2. Yellow/orange skin 3. Decreased acne (retenoic acid)
Function of vitamin D 1. Increase in Ca and P absoption in SI 2. Decrease calcium excreation in kidneys 3. Removes Ca from bone to increase the Ca concentration in blood 4. Stimulates cell differentiation
Vitamin E Functions Antioxydant : 1. Membrane intergrity 2. Hinders free radicals 3. Decreases LDL oxidation
Functions of vitamin K 1. Blood clotting 2. Bone formation (glutamic acid)
Where is endogenous vitamin K produced and what is its name? Made by bacteria in large intestine and named menaquinone
Exogenous vitamin K is called what and found where? Phylloquinone and found in plants
Vitamin B12 digestion: 3 steps 1. Protein releases by HCL and pepsin in stomach 2. B12 binds to R Protein. R Protein is removed by proteases. 3. B12 binds to intrinsic factor which is secreted by the parietal cells
Vitamin B12 is absorbed as what and where? It is absorbed by B12-IF complex by receptor mediated endocytosis in illeum
Can vitamins be stored in the body? Yes, fat soluble vitamins can as well as B12
What makes vitamin A soluble? Bile : Proteases in the stomach
Through what mechanism is vitamin A absorbed? Passive diffusion
Where is preformed vitamin A found? 1. Animal products 2. Retinol esters
Where is proformed vitamin A found? In orange, yellow and red plant products
In what instance does our body use carotenoids instead of retinol for vitamin A? If it is low but it is much slower
In the enterocytes, vitamin A is bound to what and reesterified by what? Bound to CRBP and reesterified by LRAT
Proformed vitamin A is oxidized to form what? Retinal
If vitamin A levels are low, it is reduced to what? Retinol
If vitamin A levels are low, it is reduced to retinol and esterified by what? LRAT
Retinal is oxidized to what? Retinoic acid
What is the function of retinol? Reproduction and growth
What is the function of retinal Vision
What is the function of retinoic acid? Cell differentiation
What is the active form of vitamin D? Cacitrol
Natural tocopherols require what kind of digestion? None
Synthetic tolopherols require what kind of digestion? Esterases
Tocotrienols require what kind of digestion? Esterases
What is precursor to vitamin D? Cholesterol (dehydrocholesterol)
Obese patients may be lacking in what vitamin? D
Is there any digestion required for vitamin D? No!
How is vitamin D absorbed? Passive diffusion as vitamin D3 (inactive)
Vitamin D is absorbed in what form? D3 - Inactive
Vitamin D binding protein (DBP) transports vitamin D to where? Kidneys and Liver
Are vitamin E supplements as active s dietary vitamin E? No
Vitamin A and E are both what? Esterified
What does esterified mean? Bound to a fatty acid
How are vitamin A and E packed? Chylomicrons
What kind of digestion for vitamin K? None
What helps absorbe vitamin K? Bile
Vitamin K in packed into what for transport? Chylomicrons
Digestion of vitamin A Proteases in stomach and SI... esterase removes FA
Absorption of vitamin A Passive diffusion in SI and reesterified in enterocytes
Transport for vitamin A RE and carotenoids are packed in chylomicrons where retinoic acid is packed in albumin
Absoprtion for vitamin D Passive diffusion in micelles
Transport of vitamin D 40% chylomicrons and 60% DBP (calcitrol)
Digestion of synthetic vitamin E Esterase
Aboprtion of phyloguinone Passive diffusion into micells
Absorption of menquinone Passive diffusion into ileum and LI
Transport of vitamin E Cylomicrons
Is digestion needed for vitamin C? No, Ascorbic acid is oxidized into dehydroascorbic acid
How is ascorbic acid absorbed? Active transport: SVCT1 and SVCT2
How is dehydroascorbic acid absorbed? Facilitated diffusion: it is quickly reduced back to ascorbic
Absorption of vitamin C increases or decreases with consumption? Decreases
What also decreases absorption of vitamin C? Glucose, Large doses of iron
Vitamin C is transported via what? Free ascorbic acid in plasma
What is the natural form of folate? Folate
What is the synthetic form of folate? Folic acid
What type of digestion for folic acid? None
What type of digestion for folate? Residue need to be removed with conjugase in brush border. Glutamate is removed by conjugase in SI.
Folate is absorbed by what? By active transport (foods) or by passive diffusion (pharmacological doses) in the SI. Whithin the enterocyte folate is reduced to tetrahydrofolate and methylated to 5-methyl THF
What are the carriers for folate? Folate binding protein (FBP) and reduced folate transporter (RFT)
How is 5-methyl tetrahydrofolate transported? It is transported as free in the plasma
B12 is transported via what in blood? Trancobalamins
Ca is absorbed via what carrier? Calbindin 9K
How is calcium transported? It can be transported freely as calcium or bound to albumin or prealbumin
What is and example of a sphingophosphatide and where is it found? Spingomyelin and it is found in plasma membranes of animal cells and in the myelin sheaths of the nerves
Name 2 sphingolipids but that are not sphingophospatides 1. Cerebroside 2. Ganlioside
How are gangliosides diffrent than cerebrosides? Cerbreoside is a ceramide + glucose or galactose and a ganglioside is a ceramide + oligosaccharide
Tay-sachs Ganliosides
Neimann-pick Spingomyelin
Sandhoof's Gangliosides
Gaucher's Glucocerebroside
Farber Ceramide
Krabbe Galactocerebroside
What is important for determing blood type? Gangliosides
Ceramides are composed of what? Sphingosine + Fatty acid
What is the function of gangliosides? Cell signaling
Created by: LrB