Question

1/Which coenzyme is required for aminotransferases?

Select one:

A. Flavin adenine dinucleotide (FAD)

B. Thiamin pyrophosphate (TPP)

C. Pyridoxal phosphate (PLP)

D. Nicotinamide adenine dinucleotide (NAD+)

E. Folate

2/Which amino acid needs to be supplemented in the diet of patients with Phenylketonuria?

Select one:

A. Tyrosine B. Arginine C. Methionine D. Phenylalanine E. Tryptophan

3/5-fluorouracil is an anticancer drug that interferes with which of the following processes?

Select one:

A. Pyrimidine synthesis

B. Purine catabolism

C. Pyrimidine catabolism

D. Purine salvage

E. Purine synthesis

4/ATP may be produced by substrate-level phosphorylation using which of the following compounds?

Select one:

A. 1,3 bisphosphoglycerate

B. Fructose 6-phosphate

C. Fructose 1,6-bisphosphate

D. 3-phosphoglycerate

E. Glyceraldehyde 3-phosphate

Answer 1

1. The coenzyme required by aminotransferases is Pyridoxal phosphate. The coenzyme Pyridoxal phosphate recieves the amino group from an aminoacid and transfers it to the other aminoacid in a stepwise manner.

2. The correct answer is Tyrosine.

Phenylketoneuria is a genetic disorder in which a person is not having normal enzyme phenylalanine hydroxylase. the enzyme is normally responsible for the conversion of phenylalanine to Tyrosine. however due to the non-functional enzyme, phenylalanine gets accumulated and does not result in the conversion of phenylalanine to tyrosine. therefore a person suffering from phenylketoneuria needs to be supplemented with tyrosine.

3. 5'fluorouracil is a base analogue which prevents the activity of enzyme thymidylate synthase, and thus prevent the synthesis of Thymine (a pyrimidine). therefore it interferes with the pyrimidine synthesis (option A)

4. During glycolysis, substrate level phosphorylation occurs when 1,3-Diphosphoglycerate gets converted to 3-phosphoglycerate with the help of enzyme phosphoglycerokinase. therefore the option A is the correct.