Description : The enzyme aspartate transcarbamoylase of pyrimidine biosynthesis is inhibited by (A) ATP (B) ADP (C) AMP (D) CTP
Last Answer : Answer : D
Description : Cytosolic carbamoyl phosphate synthetase is inhibited by (A) UTP (B) CTP (C) PRPP (D) TMP
Last Answer : Answer : A
Description : Cytosolic carbamoyl phosphate synthetase is activated by (A) Glutamine (B) PRPP (C) ATP (D) Aspartate
Last Answer : Answer : B
Description : Phosphofructokinase key enzyme in glycolysis is inhibited by (A) Citrate and ATP (B) AMP (C) ADP (D) TMP
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 : 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
Last Answer : Answer : C
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
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
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 : PRPP synthetase is allosterically inhibited by (A) AMP (B) ADP (C) GMP (D) All of these
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 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 : In the biosynthesis of c-DNA, the joining enzyme ligase requires (A) GTP (B) ATP (C) CTP (D) UTP
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 : G-proteins have a nucleotide binding site for (A) ADP/ATP (B) GDP/GTP (C) CDP/CTP (D) UDP/UTP
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 : 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 : Pyrimidine biosynthesis begins with the formation from glutamine, ATP and CO2, of (A) Carbamoyl aspartate (B) Orotate (C) Carbamoyl phosphate (D) Dihydroorotate
Description : Along with CO2, NH3 and ATP, the amino acid that is needed in urea cycle is (A) Alanine (B) Isoleucine (C) Aspartate (D) Glycine
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 : Isocitrate dehydrogenase is allosterically inhibited by (A) Oxalosuccinate (B) α-Ketoglutarate (C) ATP (D) NADH
Description : The reaction catalysed by phosphofructokinase (A) Is activated by high concentrations of ATP and citrate (B) Uses fruitose-1-phosphate as substrate (C) Is the rate-limiting reaction of the glycolytic pathway (D) Is inhibited by fructose 2, 6-bisphosphate
Last Answer : C
Description : All of the following statements about the enzymic complex that carries out the synthesis of ATP during oxidative phosphorylation are correct except (A) It is located on the matrix side of the inner ... inhibited by oligomycin (C) It can exhibit ATPase activity (D) It can bind molecular O2
Last Answer : D
Description : Myeloma cells are lacking in (A) TMP synthetase (B) Formyl transferase (C) HGPRT (D) All of these
Description : Tetrahydrofolate is required as a coenzyme for the synthesis of (A) UMP (B) CMP (C) TMP (D) All of these
Description : For the synthesis of TMP from dump, a coenzyme is required which is (A) N10- Formyl tetrahydrofolate (B) N5- Methyl tetrahydrofolate (C) N5, N10- Methylene tetrahydrofolate (D) N5- Formimino tetrahydrofolate
Description : Amethopterin and aminopterin decrease the synthesis of (A) TMP (B) UMP (C) CMP (D) All of these
Description : Xanthosine monophosphate is an intermediate during de novo synthesis of (A) TMP (B) CMP (C) AMP (D) GMP
Description : Inosine monophophate is an intermediate during the de novo synthesis of (A) AMP and GMP (B) CMP and UMP (C) CMP and TMP (D) All of these
Description : d-UMP is converted to TMP by (A) Methylation (B) Decarboxylation (C) Reduction (D) Deamination
Description : A purine nucleotide is (A) AMP (B) UMP (C) CMP (D) TMP
Description : Congenital deficiency of ornithine transcarbamoylase causes (A) Hyperammonaemia type I (B) Hyperammonaemia type II (C) Hyperornithinaemia (D) Citrullinaemia
Description : Hyperammonaemia type I results from congenital absence of (A) Glutamate dehydrogenase (B) Carbamoyl phosphate synthetase (C) Ornithine transcarbamoylase (D) None of these
Description : Increased urinary excretion of orotic acid can occur in deficiency of (A) Orotate phosphoribosyl transferase (B) OMP decarboxylase (C) Mitochondrial ornithine transcarbamoylase (D) Any of the above
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
Description : An enzyme which is excreted in urine is (A) Lactase dehydrogenase (B) Amylase (C) Ornithine transcarbamoylase (D) None of these
Description : Transfer of the carbamoyl moiety of carbamoyl phosphate to ornithine is catalysed by a liver mitochondrial enzyme: (A) Carbamoyl phosphate synthetase (B) Ornithine transcarbamoylase (C) N-acetyl glutamate synthetase (D) N-acetyl glutamate hydrolase
Description : Control of urea cycle involves the enzyme: (A) Carbamoyl phosphate synthetase (B) Ornithine transcarbamoylase (C) Argininosuccinase (D) Arginase
Description : A common substrate of HGPRTase, APRTase and PRPP glutamyl amidotransferase is (A) Ribose 5 phosphate (B) Phosphoribosyl pyrophosphate (C) Hypoxanthine (D) Adenosine
Description : All the following statements about primary gout are true except (A) Its inheritance is X-linked recessive (B) It can be due to increased activity of PRPP synthetase (C) It can be ... activity of hypoxanthine guanine phosphoribosyl transferase (D) De novo synthesis of purines is increased in it
Description : The following abnormality in PRPP synthetase can cause primary gout: (A) High Vmax (B) Low Km (C) Resistance to allosteric inihbition. (D) All of these
Description : The available PRPP is used preferentially for (A) De novo synthesis of purine nucleotides (B) De novo synthesis of pyrimidine nucleotides (C) Salvage of purine bases (D) Salvage of pyrimidine bases
Description : Salvage of purine bases is regulated by (A) Adenosine phosphoribosyl transferase (B) Hypoxanthine guanine phosphoribosyl transferase (C) Availability of PRPP (D) None of these
Description : The first reaction unique to purine nucleotide synthesis is catalysed by (A) PRPP synthetase (B) PRPP glutamyl amido transferase (C) Phosphoribosyl glycinamide synthetase (D) Formyl transferase
Description : AMP is an allosteric inhibitor of (A) PRPP synthetase (B) Adenylosucciante synthetase (C) Both (A) and (B) (D) None of these