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NUT2001 > Vitamins > Flashcards

Vitamins Flashcards

1
Q

Forms of Vitamin k

A

K1 - Phylloquinone (plants)

K2 - Menaquinone (bacteria)

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2
Q

Vitamin K Absorption

A

80% of K1 is absorbed
Proximal intestine
Fat soluble so enter chylomicron
Travels to Liver

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3
Q

How vitamin K travel to liver

A 
50% in triglyceride
25% in LDL
25% in HDL
Effectiveness depends on ApoE gene
E2 best and E4 the worst
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4
Q

Vitamin K function

A

Blood coagulation

Bone protein

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5
Q

Vitamin K make Gla

A

Co-factor for carboxylase enzyme for carboxylation of pro-thrombin
Glu -> Gla

Warfarin interrupts vit K cycle and no Gla made
Leading to uncarboxylated proteins in blood

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6
Q

Vitamin K and blood coagulation

A 
Factor II (prothrombin) synthesised in liver containing Gla protein
So no blood clot
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7
Q

Vitamin K and Bone Protein

A

Osteoblasts produce ostocalcin which need Gla
Matric also has Gla
Protein S

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8
Q

Vitamin K Deficiency

A

Increased clotting time
Circulatin uncarboxylate prothrombin
Decreased bone density

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9
Q

Vitamin A forms

A

Retinol
Retinal
Retinoic acid

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10
Q

1 retinol activity

A

1mg pre-formed vtiamin A

2mg beta-carotene

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11
Q

Digestion Vitamin A

A

Reinyl esters hydrolysed in duodenum via pancreatic lipase

Enter cell through SR-B1 and CD36 transporter

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12
Q

Absorption Vitamin A

A

Incorporated into micelles
Retinol is re-esterified to retinyl ester (sometimes turn to trans form which is useless)
Enter target cell by facilitated diffusion by SR-B1

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13
Q

Cleaving beta-caretone

A

BCO1 - Cleaves 5-15’ creating two retinol
BCO2 - cleaves 9-10’ creating one
(we have evolved to have BCO2 as eat meat)

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14
Q

Deficiency vitamin A

A

Pupils cannot constrict mormally so night blindness
Impaired maintanence of epithelial tissues
Impaired neutrophils and macrophages
Decreased natural killer cells
Decreased T-helper cell

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15
Q

B vitamin overview

A

Water soluble vitamins with different structures but similar function. Participate in all metabolic pathways.

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16
Q

B1

A

Thiamine
Grains
Meat

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17
Q

B2

A

Riboflavin
Grains
Dairy

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18
Q

B3

A

Niacin
Grains
Meat

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19
Q

B5

A

Pantothenic acid
Eggs
Liver

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20
Q

B6

A

Pyridoxal

Meat

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21
Q

B7

A

Biotin
Egg
Liver
Salmon

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22
Q

B9

A

Folate
Grains
Fruit and veg

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23
Q

B12

A

Meat

Dairy

24
Q

Thiamine Absorption

A

Duodenum and jejunum
Active transport or passive if high concn
Binds to albumin in blood
Absorbed in target cell via active transport
Phosphorylated to make TPP

25
Q

Thiamine Coenzymes

A

Known as TPP
Catobolise leucine, isoleucine and valine
Involved in link reaction
Make branch amino acids
Krebs cycle - Ketoglutarate dehydrogenase
Pentose pathway

26
Q

Thiamine Deficiency

A

Beri Beri wet and dry

27
Q

Riboflavin digestion

A

Protease converts Riboflavin to B2
Absorbed by active transport in duodenum and jejunum
Magnesium and high dose of B2 decrease
Enters circulation as free B2
Binds to Fibrinogen and albumin in blood
Uptake into target cell via active transport

28
Q

Riboflavin function

A 
Co-enzyme flavin adenine diucleotide (FAD) and flavin mononucleotide (FMN)
Electron carrier
TCA 
Beta oxdation
link reaction
gluthione reductase
29
Q

Riboflavin deficiency

A

Cracks around mouth, inflammation of lips and tongue, anaemia. Is rare as body can conserve

30
Q

Niacin Absorption

A

Hydrolysed to free nicotinic acid
Absorbed in stomach and duodenum by facilitated diffusion (Na dependent)
High leucine and low tryptophan and niacin inhibit absorption
Transport in blood free
Cellular uptake via facillitated diffusion

31
Q

Niacin function

A 
NAD+ and NADP+
Glycolysis
TCA
beta oxidation
link reaction
Malonyl pathway
32
Q

Niacin Deficiency

A 
Pellagra 
cracking skin
Hyperkeratosis
Hyperpigmentation
Dermatitis
DIarrhoea
Delirium
33
Q

Niacin toxicity

A

Dilation of blood vessels

Liver damage

34
Q

Pantothenic acid digestion

A

CoA and ACP degraded in intestine
Yield pantothenic acid
Absorbed via facilitated diffusion at low concentration
Cellular uptake mediated by SMVT and converted to CoA and ACP

35
Q

Pantothenic acid function

A

CoA
Beta oxidation
fat synthesis
Link reaction

36
Q

Pantothenic acid deficiency

A

Burning foot
Abdominal pain and nausea
Cramps
Alopecia

37
Q

Pyridoxine Absorption

A

Dephosphorylated by alkaline phosphate in mucosa
Absorbed passively
Binds to albumin in plasma
Stored in muscle, liver, brain, kidney and spleen
Urine reflects intake

38
Q

Pyridoxine Function

A

Needed to transfer amine group
Co-enzyme for homocysteine to cysteine
Glycolysis

39
Q

Pyridoxine Deficiency

A 
Caused by tuberculosis
Microcytic anaemia
Secondary pellagra
Irritability 
Depression
Convulsions
Raised plasma homocysteine concn
40
Q

Pyridoxine Toxicity

A

Nerve and skin damage

41
Q

Biotin Absorption

A

Protease creates Biocytin and biotinides
These are further hydrolysed to create free biotin
Absorbed along small intestine by sodium dependent transporters
or passively at high concentration

42
Q

Biotin Function

A

Prosthetic group for: pyruvate carboxylase (link)
acetyl CoA carboxylase
Propionyl CoA carboxylase
Beta-methylcrotonyl-CoA carboxylase
Involved in gluconeogenesis and fatty acid synthesis

43
Q

Biotin Deficiency

A 
Not severe in adults
Burning foot
Less coordinated
In infants
Dermatitis, alopecia and ketosis
44
Q

Folate Absorption

A

Hydrolysed to monoglutamate via a zinc dependent carboxypeptidase
Absorbed by active pH transporter (needs H+)
Transported to liver via portal circulation
Released in to peripheral tissue carried by albumin
Taken up by cells via folate transporter

45
Q

Folate Function

A

Carries methyl group
Amino acid metabolism (Homocysteine to methionine)
Pyrimidine and purine synthesis

46
Q

Folate deficiency

A

Hyperhomocysteinemia
Megaloblastic anaemia
Reduces synthesis of neurotransmitters
First 12 weeks of pregnancy consume 400ug a day

47
Q

Cobalamin Absorption

A 
Bile constantly recirculated
Bile enter small intestine
B12 binds to IF
90% reabsorbed in ileum
Saturate with intake higher than 1.5-2.5ug
48
Q

Cobalamin Metabolism

A

Found as adenosycobalamin or methyl cobalamin acts as carrier of 1-C units
MeCbl needed for 5-methylTHF to tetrahydrofolate by MS Co-enzyme in the reaction of homocysteine to methionine
Co-enzyme in the conversion of propionyl CoA to succinyl CoA

49
Q

Cobalamin Deficiency

A

Vegans
Pernicious anaemia
Demyelination nerve cells
Hyperhomosysteinemia

50
Q

Vitamin E overview

A

fat soluble
Alpha - 3 methyl groups
Beta and yonder - 2 methyl groups
Sigma - 1 methyl group

51
Q

Vitamin E Absorption

A 
Hydrolysed by pancreatic esterase
Facilitated diffusion involving SR-B1
Incorporated into chylomicron
Binds to alpha-tocopherol transfer protein
Delivered to VLDL
Redistributed into lipoprotein
52
Q

Vitamin E Structural function

A

Incorporated into membrane and cytoplasm

53
Q

Vitamin E chemical function

A

Breaks oxidation chain to protect PUFA
Free radical steal hydrogen from in PUFA
Making a peroxy radical
Peroxy radical normallyt hen steal from neighbouring instead Vitamin E quenches
Makes lipid hydroperoxide
Secondary vitamin E reacts with lipid hydroperoxide to make lipid alcohol

54
Q

Vitamin E Defficiency

A

Rare unless associated with fat malabsorption
Myopathies
Neuropathies

55
Q

Vitamin C Absorption

A

If high concentration absorbed passively
If low concentration then active tranpost using sodium pump SVCT1
Readily transported in blood
ABsorbed into tissue with SVCT2

56
Q

Vitamin C Fnction

A

Quenches Vitamin E radical
Maintain iron and copper as ions
Formation of adrenalin and noradrenaline

57
Q

Vitamin C deficiency

A

Scurvy

NUT2001 (4 decks)

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