Nucleic Acids - Mock Test 41

Question 401

All of the following statements about thioredoxin reductase are true except?

A) It requires NADH as a coenzyme B) Its substrates are ADP, GDP, CDP and UDP C) It is activated by ATP D) It is inhibited by dADP

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Question 402

Tetrahydrofolate is required as a coenzyme for the synthesis of?

A) UMP B) CMP C) TMP D) All of these

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Question 403

During de novo synthesis of pyrimidine nucleotides, the first ring compound to be formed is?

A) Carbamoyl aspartic acid B) Dihydro-orotic acid C) Orotic acid D) Orotidine monophosphate

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Question 404

All the enzymes required for de novo synthesis of pyrimidine nucleotides are cytosolic except?

A) Carbamoyl phosphate synthetase B) Aspartate transcarbamoylase C) Dihydro-orotase D) Dihydro-orotate dehydrogenase

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Question 405

CTP synthetase forms CTP from?

A) CDP and inorganic phosphate B) CDP and ATP C) UTP and glutamine D) UTP and glutamate

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Question 406

For synthesis of CTP and UTP, the amino group comes from?

A) Amide group of Asparagine B) Amide group of glutamine C) α-Amino group of glutamine D) α-Amino group of glutamate

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Question 407

Amethopterin and aminopterin decrease the synthesis of?

A) TMP B) UMP C) CMP D) All of these

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Question 408

Conversion of uridine diphosphate into deoxyuridine diphosphate requires all the following except?

A) Ribonucleotide reductase B) Thioredoxin C) Tetrahydrobiopterin D) NADPH

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Question 409

The first pyrimidine nucleotide to be formed in de novo synthesis pathway is?

A) UMP B) CMP C) CTP D) TMP

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Question 410

Nitrogen at position 3 of pyrimidine nucleus comes from?

A) Glutamine B) Glutamate C) Glycine D) Aspartate

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