Vitamin B2 & Deficiency
A 69 year old alcoholic developed carcinoma of lower lips. Consider the following statements:
Assertion: Squamous cell carcinoma is most often and site of predilection is between the midline and commissure of the lip
Reason: Riboflavin deficiency may be responsible for cancer in alcoholics
| A |
Both Assertion and Reason are true, and Reason is the correct explanation for Assertion |
|
| B |
Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion |
|
| C |
Assertion is true, but Reason is false |
|
| D |
Assertion is false, but Reason is true |
A 69 year old alcoholic developed carcinoma of lower lips. Consider the following statements:
Assertion: Squamous cell carcinoma is most often and site of predilection is between the midline and commissure of the lip
Reason: Riboflavin deficiency may be responsible for cancer in alcoholics
| A |
Both Assertion and Reason are true, and Reason is the correct explanation for Assertion |
|
| B |
Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion |
|
| C |
Assertion is true, but Reason is false |
|
| D |
Assertion is false, but Reason is true |
Riboflavin deficiency is assessed by ‑
| A |
Transketolase |
|
| B |
Glutathione reductase |
|
| C |
PDH |
|
| D |
None |
Riboflavin deficiency is assessed by ‑
| A |
Transketolase |
|
| B |
Glutathione reductase |
|
| C |
PDH |
|
| D |
None |
Ans. is ‘b’ i.e., Glutathione reductase
Riboflavin (Vitamin B2)
- Riboflavin is also called Warburg yellow enzyme.
- Riboflavin provides the reactive moieties of the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
- Flavin coenzymes are involved in oxidoreduction reactions as electron carriers.
- These reactions include the mitochondrial respiratory chain, key enzymes in fatty acid and amino acid oxidation and the citric acid cycle.
Flavin dependent (flavoprotein) enzymes are :
- FMN dependent : L-amino acid oxidase, NADH dehydrogenase.
- FAD dependent : Complex II of respiratory chain, microsomal hydroxylase system, D-amino acid oxidase, xanthine oxidase, succinate dehydrogenase, acyl-CoA dehydrogenase, glycerol-3-phosphate dehydrognenase, pyruvate dehydrognenase, a-ketoglutarate dehydrogenase.
- Deficiency of riboflavin is charcterized by cheilosis, desquamation and inflammation of tongue, and a seborrheic dermatitis.
- Riboflavin nutritional status is assessed by measurement of activation ofglutathione reductase by FAD added in vitro.
Riboflavin is a constituent of ‑
| A |
FMN |
|
| B |
NAD |
|
| C |
PLP |
|
| D |
THF |
Riboflavin is a constituent of ‑
| A |
FMN |
|
| B |
NAD |
|
| C |
PLP |
|
| D |
THF |
Ans. is ‘a’ i.e., FMN
- Riboflavin is also called Warburg yellow enzyme.
- Riboflavin provides the reactive moieties of the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
- Flavin coenzymes are involved in oxidoreduction reactions as electron carriers.
- These reactions include the mitochondrial respiratory chain, key enzymes in fatty acid and amino acid oxidation and the citric acid cycle.
