Vitamin B9 - Folic acid

Question 1

absorption of folic acid

Answer 1

folic acid is abs. to int. mucosal cell: 1. folic acid -> FH2 2. FH2 -> FH4 - both FH2 and FH4 can be absorbed passively to the liver

Question 2

Transport of B9

Answer 2

active transport to other cell types (than liver)

Question 3

forms of B9

Answer 3

FH4 is the active form of folic acid

Question 4

excretion

Answer 4

folic acid is excreted in faeces and urine

Question 5

cofactor used in synth of NH4

Answer 5

ascorbic acid

Question 6

vitamin antagonist

Answer 6

• *ametopterine**:
• methotrexate; anti-tumor effect (chemo)
• trimethoprim: anti-microbial
• *5-fluoruracil**: inhibit thymidilate synthase (DNA synth in eu) =>antitumor effect
• *sulphonamides:** antimicrobial (folic acid cant be tp. tp microbes: no uptake, then have to synth. intracellularly)

Question 7

biochemical role

Answer 7

donator and acceptor of C1 fragments

Question 8

deficiency symptoms

Answer 8

anaemia: enough hb, but low cell division

slow growth