Vandopløselige vitaminer/ Flashcards
Kap 11 (44 cards)
How many water soluble vitamins are there?
- 9 (8 B-vitamins, 1 C vitamin)
- all b-vitamins are a part of the metabolism
What is the definition of vitamins?
- organic compounds needed for growth
- something we cant synthesize ourselves
- Needed in very small amount
- Co-factors
- Not a source of calories
Thiamin diphosphat is a coenzyme for which enzymes in metabolic pathways?
Thiamine diphosphate (B1 vitamer) er coenzym for:
- Pyruvat dehydrogenase
- alpha-ketoglutarate dehydrogenase
- Keto acid dehydrogenase
- Transketolase in PPP
Which diseases are related to B1 deficiency?
- Dry beriberi
- Generally too little acetyl CoA and too much lactate and pyruvate
- Acidosis
Vitamin B2, riboflavin, is a component in which two flavocoenzymes?
- Riboflavin monophosphate (FMN)
- Flavin adenine dinucleotide (FAD)
Which diseases is related to B2 deficiency?
ariboflavinosis
What is niacin?
- Vitamin B3
- Not strictly a vitamin but acts as one
- Can be synthesized in the body from tryptophan
- Necessary for protein and fat metabolism, healthy skin, gastrointestinal and CNS function, production of sex hormones
What are sources of niacin?
Enriched grains cereal, beef, turkey, fish, asparagus, peanuts
Also in corn, but bound by a protein, so should be soaked in water
Which diseases are related to Niacin deficiency?
- pellagra
- lack of extracting energi from protein
Mention a vitamin C
ascorbat
Can humans and other primates synthesize ascorbat (vitamin C)?
No, because of multiple mutations in the gene encoding gulonolactone oxidase
Where is vitamin C taken up in the body?
In The jejunum via the intestinal brush border and buccal mucosa
What are the functions of vitamin C?
- Reduces Fe3+ to Fe2+
- Proline- and lysine hydroxylases (coenzym til dem)
- Dannelse af hydroxyproline (collagen dannelse)
- Reduces Cu2+ til Cu+
- Antioxidant
Which diseases are linked with vitamin C deficiency?
Scurvy (skørbug??),
needed to organize collagen fiber (in skin, teeth and bone)
Which vitamin contains a metal, and which metal?
B12
metal = cobalt
- is in foods of animal origin
How is vitamin B12 released from the food?
by gastric acid, pepsin and duodenal enzymes together with intrinsic factor
What are some of the important roles of vitamin B12?
Required as coenzyme for:
- Isomerization of L-methylmalonyl CoA to succinyl CoA. (important for hemoglobin synthesis)
- Methylation of homocysteine to methionine. (important in intracellular synthesis of folate coenzyme)
Where is B12 absorbed in the body?
- in the ileum as an active process
- intrinsic factor (IF) is needed for uptake in the ileum, in a 1:1 ratio
- Required Calcium ions and neutral pH
How much vitamin B12 does the body store?
Normally 3-4 mg
Stored in the liver
Sufficient for approx. 3 years of no extra B12
Vitamin B12 deficiency can be caused by?
- Inadequate dietary intake
Vegans eg. - Intestinal malabsorption. Commonly due to lack of intrinsic factor gastrointestinal disease
Where are the folates absorbed?
in the upper jejunum
When is folate especially important?
In early pregnancy
What vitamins are parts of electron carriers?
Flavin in FADH
Niacinamid in NADH/NADPH
Hvilket vitamin er pyridoxal phosphat?
Vitamin B6
