B2 Riboflavin

Question 1

What vitamin functions as a coenzyme as FMN/FMNH2?

Answer 1

riboflavin

riboflavin is primarily found in the body as an integral componment of the coenzymes

FAD - flavin adenine dinucleotide
FMN - flavin mononucleotide

Question 2

What is the best dietary source of riboflavin?

Answer 2

milk and milk products such as cheeses are thought to contribute most dietary riboflavin

other good sources include
eggs
meat
legumes

green vegetables are faily good sources
furit and grains are minor contributors of riboflavin

Question 3

The activity of erythrocyte glutathione reductase is useful for assessing the adequacy of which vitamin?

Answer 3

riboflavin

the most sensitive method for determining riboflavin nutriture is to measure the activity of erythrocyte glutatione reductase

erythrocyte glutathione reductase requires FAD as a coenzyme.

In cases of riboflavin deficiency or marginal riboflavin status the activity of glutthione reductase is limited.

Question 4

Excretion of fluorescent orange yellow urine follows oral ingestion of which vitamin?

Answer 4

riboflavin

Question 5

Which B vitamins are necessary in the pyruvate dehydrogenase complex?

Answer 5

thiamin (TPP)
riboflavin (FAD)
niacin (NAD)
pantothentic acid (CoA-SH)
lipoic acid

pyruvate dehydrogenase is a multicomplex enzyme that catalyzes the conversion of pyruvate to acetyl CoA so it can enter the TCA cycle

Question 6

What is the function of FAD and FMN?

Answer 6

They act as oxidizing agents.

They accept a pair of Hydrogen atoms

Their reduced forms are

FADH2
FMNH2

Question 7

What are some reactions that require FAD or FMN?

Answer 7

1. Vitamin B6 metabolism
2. Folate metabolism
3. Niacin synthesis
4. Choline catabolism
5. Reduction of glutathione
6. Electron transport chain
7. Oxidative decarboxylation reactions by dehydrogenase enzymes
8. Beta-oxidation of fatty acids
9. Synthesis of neurotransmitters
10. DNA synthesis