Nucleotides

Question 1

Which statement best describes Xanthine?
a) Direct precursor of Guanine
b) it covalently binds to allopurinol
c) it is oxidized to form uric acid
d) it is oxidized to form hypoxanthine
e) it is a substrate rather than a product of the enzyme Xanthine oxidase

Answer 1

It is oxidized to form uric acid

Question 2

MethylatedHydro cyclic bases of plants include all except
a) caffeine
b)Theophylline
c) theobromine
d) Thymine

Answer 2

D) Thymine

Question 3

which of the following is not an anti-cancer drug?
a) 5 fluorouracil
b) 5 iododuracil
c) 3-deoxyuridine
d) 6-thioguanine
e) pseudouridine

Answer 3

C) 3-deoxyuridine

Question 4

feedback inhibition of pyramid in nucleotide synthesis can occur by which of the following?
a) increased activity of Carbamoyl phosphate synthetase
b) increase activity of Aspartate transcarbamoylase
c) CTP Allosteric effects
d) UMP competitive inhibition
e) TTP allosteric effects

Answer 4

c) CTP allosteric effects

Question 5

which base derivative can serve as a precursor for the synthesis of two of the other pyrimidine base derivatives?
a) Cystidine Triphosphate
b) Uridine mono phosphate
c) Adenosine mono phosphate
d) Deoxy thymdine mono phosphate

Answer 5

B)Uridine mono phosphate

Question 6

Purine nucleotide biosynthesis can be inhibited by

Answer 6

Adenosine mono phosphate

Question 7

which of the following contribute nitrogen atoms to both purine and pyrimidine rings

Answer 7

Aspartate

Question 8

Which substrate is required for purine biosynthesis

Answer 8

PRPP

Question 9

which is the analogue of hypoxanthine

Answer 9

Allopurinol

Question 10

The conversion of inosine mono phosphate

Answer 10

GMP requires glutamine

Question 11

Mycophenolic acid inhibits, which enzyme in the synthesis of nucleotides

Answer 11

IMP dehydrogenase