Description : Aspartate transcarbamoylase is inhibited by (A) CTP (B) PRPP (C) ATP (D) TMP
Last Answer : Answer : A
Description : An enzyme of pyrimidine nucleotide biosynthesis sensitive to allosteric regulation is (A) Aspartate transcarbamoylase (B) Dihydroorotase (C) Dihydroorotate dehydrogenase (D) Orotidylic acid decarboxylase
Description : Phosphofructokinase key enzyme in glycolysis is inhibited by (A) Citrate and ATP (B) AMP (C) ADP (D) TMP
Description : An enzyme common to de novo synthesis of pyrimidine nucleotides and urea is (A) Urease (B) Carbamoyl phosphate synthetase (C) Aspartate transcarbamoylase (D) Argininosuccinase
Last Answer : Answer : B
Description : Pyrimidine biosynthesis begins with the formation from glutamine, ATP and CO2, of (A) Carbamoyl aspartate (B) Orotate (C) Carbamoyl phosphate (D) Dihydroorotate
Last Answer : Answer : C
Description : In the biosynthesis of c-DNA, the joining enzyme ligase requires (A) GTP (B) ATP (C) CTP (D) UTP
Description : De novo synthesis of pyrimidine nucleotides is regulated by (A) Carbamoyl phosphate synthetase (B) Aspartate transcarbamoylase (C) Both (A) and (B) (D) None of these
Description : 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
Last Answer : Answer : D
Description : The enzyme phosphoenolpyruvate carboxykinase catalyses the conversion of oxaloacetate to phosphoenolpyruvate requires (A) ATP (B) ADP (C) AMP (D) GTP
Description : The enzyme acyl-CoA synthase catalyses the conversion of a fatty acid of an active fatty acid in the presence of (A) AMP (B) ADP (C) ATP (D) GTP
Description : G-proteins have a nucleotide binding site for (A) ADP/ATP (B) GDP/GTP (C) CDP/CTP (D) UDP/UTP
Description : The 2 energy rich compounds needed for protein biosynthesis are (A) ATP and GTP (B) ATP and UTP (C) ATP and CTP (D) ATP and TTP
Description : PRPP synthetase is allosterically inhibited by (A) AMP (B) ADP (C) GMP (D) All of these
Description : In purine biosynthesis ring closure in the molecule formyl glycinamide ribosyl-5- phosphate requires the cofactors: (A) ADP (B) NAD (C) FAD (D) ATP and Mg++
Description : 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
Description : The ability of CTP to bind to aspartate carbamoyltransferase and shut down the synthesis of more A- enzyme induction B- enzyme repression C- feedback inhibition of enzyme activity D- none of these
Last Answer : feedback inhibition of enzyme activity
Description : An enzyme of pyrimidine nucleotides biosynthesis regulated at the genetic level by apparently coordinate repression and derepression is (A) Carbamoyl phosphate synthetase (B) Dihydroorotate dehydrogenase (C) Thymidine kinase (D) Deoxycytidine kinase
Description : Cyclic AMP can be formed from (A) AMP (B) ADP (C) ATP (D) All of these
Description : UDP and UTP are formed by phosphorylation from (A) AMP (B) ADP (C) ATP (D) GTP
Description : Allsoteric activator of glutamate dehydrogenase is (A) ATP (B) GTP (C) ADP and GDP (D) AMP and GMP
Description : Allosteric inhibitor of glutamate dehydrogenase is (A) ATP (B) ADP (C) AMP (D) GMP
Description : PRPP glutamyl amidotransferase, the first enzyme uniquely committed to purine synthesis is feed back inhibited by (A) AMP (B) IMP (C) XMP (D) CMP
Description : The first pyrimidine nucleotide to be formed in de novo synthesis pathway is (A) UMP (B) CMP (C) CTP (D) TMP
Description : The first true pyrimidine ribonucleotide synthesized is (A) UMP (B) UDP (C) TMP (D) CTP
Description : Nucleotide found free in the cells is: (a) CAMP (b) AMP (c) ADP (d) ATP
Last Answer : Ans. ((d))
Description : Which one of the following concerns photophosphorylation? (a) ADP + AMP ATP Light energy (b) ADP + Inorganic PO4 ATP Light energy (c) ADP + Inorganic PO4 ATP (d) AMP + Inorganic PO4 ATP
Last Answer : ) AMP + Inorganic PO4 ATP
Description : What has the most energy in its chemical bonds? a) AMP b) ADP c) ATP d) All are equal
Last Answer : ANSWER: C -- ATP
Description : Cytosolic carbamoyl phosphate synthetase is inhibited by (A) UTP (B) CTP (C) PRPP (D) TMP
Description : All the following statements about charging of tRNA are correct except (A) It is catalysed by amino acyl tRNA synthetase (B) ATP is converted into ADP and Pi in this reaction (C) The enzyme recognizes the tRNA and the amino acid (D) There is a separate enzyme for each tRNA
Description : Which one of the following contributes nitrogen atoms to both purine and pyrimidine rings? (A) Aspartate (B) Carbanoyl phosphate (C) Carbondioxide (D) Tetrahydrofolate
Description : Aspartate contributes the following carbon atoms of the pyrimidine nucelus: (A) C2 and C4 (B) C5 and C6 (C) C2, C4 and C6 (D) C4, C5 and C6
Description : The carbon atom at position 2 of pyrimidine nucleus is contributed by (A) CO2 (B) Glycine (C) Aspartate (D) Glutamine
Description : Nitrogen at position 3 of pyrimidine nucleus comes from (A) Glutamine (B) Glutamate (C) Glycine (D) Aspartate
Description : Nitrogen at position 1 of pyrimidine nucleus comes from (A) Glutamine (B) Glutamate (C) Glycine (D) Aspartate
Description : The carbon atoms of pyrimidine nucleus are provided by (A) Glycine and aspartate (B) CO2 and aspartate (C) CO2 and glutamate (D) CO2 and glutamine
Description : The nitrogen atoms of pyrimidine nucleus are provided by (A) Glutamate (B) Glutamate and aspartate (C) Glutamine (D) Glutamine and aspartate
Description : The two nitrogen of the pyrimidine ring are contributed by (A) Ammonia and glycine (B) Asparate and carbamoyl phosphate (C) Glutamine and ammonia (D) Aspartate and ammonia
Description : Which of the following contributes nitrogen atoms to both purine and pyrimidine rings? (A) Aspartate (B) Carbamoyl phosphate (C) CO2 (D) Glutamine
Description : The pathway of glycogen biosynthesis involves a special nucleotide of glucose. In the reaction below, NuDP stands for NuDP Glucose + glycogenn → NuDP + glycogenn+1 (A) ADP (B) GDP (C) UDP (D) CDP
Description : A substrate for enzymes of pyrimidine nucleotide biosynthesis is (A) Allopurinol (B) Tetracylin (C) Chloramphenicol (D) Puromycin
Description : Pyrimidine and purine nucleoside biosynthesis share a common precursor: (A) PRPP (B) Glycine (C) Fumarate (D) Alanine
Description : Purine biosynthesis is inhibited by (A) Aminopterin (B) Tetracyclin (C) Methotrexate (D) Chloramphenicol
Description : Cyclic AMP is formed from ATP by the enzyme adenylate cyclase which is activated by the hormone: (A) Insulin (B) Epinephrine (C) Testosterone (D) Progesterone
Last Answer : B
Description : The mRNA ready for protein synthesis has the ________ cap. (A) ATP (B) CTP (C) GTP (D) UTP
Description : CTP synthetase forms CTP from (A) CDP and inorganic phosphate (B) CDP and ATP (C) UTP and glutamine (D) UTP and glutamate
Description : Coenzymes derived from the vitamin shown below are required by enzymes involved in the synthesis of which of the following? (A) ATP (B) UTP (C) CTP (D) NADH
Description : In the reaction below, Nu TP stands for NuTP + glucose → Glucose 6–Phosphate + NuDP. (A) ATP (B) CTP (C) GTP (D) UTP
Description : The following is required for the formation of coenyzme A: (A) ATP (B) GTP (C) CTP (D) None of these
Description : Hyperargininemia, a defect in urea synthesis develops due to deficiency of the enzyme: (A) Ornithine transcarbamoylase (B) Argininosuccinase (C) Arginase (D) Argininosuccinate synthetase ENZYMES 157
Description : Enzyme deficient in Hyperammonemia type II is (A) Glutamine synthetase (B) Glutaminase (C) Ornithine transcarbamoylase (D) Carbamoylphosphate synthetase