General knowledge Flashcards
1
Q
Why humans and some other non-ruminants inefficiently utilize vitamin B12?
A
it’s produced in the lower GIT where absorption is poor
2
Q
Which 2 vitamins exist as provitamins in plant tissue?
A
Vit A and D
3
Q
Why is Vit B12 unique all of the vitamins?
A
in plant tissues is a result of micoorganism synthesis
4
Q
Best current method for detection vitamin content is?
A
(U)HPLC - ultra high performance liquid chromatography
5
Q
Retinol(Vit A1) exists in which two forms?
A
11-cis retinol
all-trans retinol
6
Q
Precursors of vit A1 (retinol).
A
Alpha, beta, and gamma carotene synthesized in plants
7
Q
Define vitaminer.
A
Compound with similar molecular struture to the vitamin and shows vitamin activity (vitamin analog)
8
Q
Functions of Vit A
A
- Constituent of visual pigments
- Prevents tumors by contact inhibition
- Regulates gene expression of proteins involved in cell growth and differentiation
- Antioxidant
- Prevents metaplasia of epithelial cells by preventing heavy weight keratin from being synthesized in cells and promoting production of mucopolysaccharides that lubricate epithelial cells
9
Q
What are the daily requirements of Vit A in 1) males 2) females 3) pregnant females 4) lactating mothers 5)infants 6) children & adolescents State the units of measurement
A
Males --> 1000 Females --> 800 Pregnant females --> 800 Lactating mothers --> 300 Infants --> 375 Children --> 400-700 micrograms of retinol
