Description : The major determinant of the overall rate of denovo purine nucleotide biosynthesis is the concentration of (A) 5-phosphoribosyl 1-pyrophosphate (B) 5-phospho β-D-ribosylamine (C) Glycinamide ribosyl-5-phosphate (D) Formylglycinamide ribosyl-5-phosphate
Last Answer : Answer : A
Description : 6-Mercapto purine inhibits the conversion of (A) IMP→ XMP (B) Ribose 5 phosphate → PRPP (C) PRPP → 5-phospho →β -D-ribosylamine (D) Glycinamide ribosyl 5-phosphate → formylglycinamide ribosyl-5-phosphate
Description : A common substrate of HGPRTase, APRTase and PRPP glutamyl amidotransferase is (A) Ribose 5 phosphate (B) Phosphoribosyl pyrophosphate (C) Hypoxanthine (D) Adenosine
Last Answer : Answer : B
Description : 5-Phosphoribosyl-1-pyrophosphate is required for the synthesis of (A) Purine nucleotides (B) Pyrimidine nucleotides (C) Both (A) and (B) (D) None of these
Last Answer : Answer : C
Description : In synthesis of Triglyceride from α-Glycero phosphate and acetyl CoA, the first intermediate formed is (A) β-diacyl glycerol (B) Acyl carnitine (C) Monoacyl glycerol(D) Phosphatidic acid
Last Answer : Answer : D
Description : In inherited deficiency of hypoxanthine guanine phosphoribosyl transferase (A) De novo synthesis of purine nucleotides is decreased (B) Salvage of purines is decreased (C) Salvage of purines is increased (D) Synthesis of uric acid is decreased
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 : A key substance in the committed step of pyrimidines biosynthesis is (A) Ribose-5-phosphate (B) Carbamoyl phosphate (C) ATP (D) Glutamine
Description : Polynucleotide chain of DNA contains (a) a nitrogenous base, deoxyribose sugar and phosphate group (b) a nitrogenous base, ribose sugar and phosphate group (c) deoxyribose sugar ribose sugar and phosphate group (d) a nitrogenous base and phosphate group only
Last Answer : Ans:(a)
Description : A molecule of ATP contains a. Ribose But No Adenine. b. Phosphate But No Ribose. c. Adenine But No Deoxyribose. d. Deoxyribose But No Thymine.
Last Answer : b. Phosphate But No Ribose.
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 enzyme required for salvage of free purine bases is (A) Adenine phosphoribosyl transferase (B) Hypoxanthine guanine phosphoribosyl transferase (C) Both (A) and (B) (D) None of these
Description : Nucleic acids can be detected by means of their absorption maxima near 260 nm. Their absorption in this range is due to (A) Proteins (B) Purines and pyrimidines (C) Ribose (D) Deoxyribose
Description : Acid hydrolysis of ribonucleic acid would yield the following major products: (A) d- deoxyribose, cytosine, adenine (B) d-ribose, thymine, Guanine (C) d-ribose, cytosine, uracil, thymine (D) d-ribose, uracil, adenine, guanine, cytosine
Description : The sugar moiety present in DNA is (A) Deoxyribose (B) Ribose (C) Lyxose (D) Ribulose
Description : The sugar moiety present in RNA is (A) Ribulose (B) Arabinose (C) Ribose (D) Deoxyribose
Description : Epimers of glucose is (A) Fructose (B) Galactose (C) Ribose (D) Deoxyribose
Last Answer : B
Description : The epimers of glucose is (A) Fructose (B) Galactose (C) Ribose (D) Deoxyribose
Description : A carbohydrate found in DNA is (A) Ribose (B) Deoxyribose (C) Ribulose (D) All of these
Description : The sugar found in RNA is (A) Ribose (B) Deoxyribose (C) Ribulose (D) Erythrose
Last Answer : A
Description : The sugar found in DNA is (A) Xylose (B) Ribose (C) Deoxyribose (D) Ribulose
Last Answer : C
Last Answer : (C) Deoxyribose
Description : The first pentose formed in HMP shunt is (A) Ribose-5-phosphate (B) Ribulose-5-phosphate (C) Xylose-5-phosphate (D)Xylulose-5-phosphate
Description : In EM pathway -2-phosphoglycerate is converted to (A) Phospho enol pyruvate (B) Enol pyruvate (C) Di hydroxy acetone phosphate (DHAP) (D) 1,3 bisphosphoglycerate
Description : Decarboxylation of α-keto acids requires (A) Thiamine pyrophosphate, FAD, NAD+ (B) Flavin mononucleotide (C) NADP+ (D) NAD+ only
Description : Difference between ribose and deoxyribose sugar. -Biology
Last Answer : answer:
Description : Difference between ribose and deoxyribose? -Biology
Description : Synthesis of RNA molecule is terminated by a signal which is recognised by (A) α-factor (B) β-factor (C) δ-factor (D) ρ
Description : Of Which warburg’s yellow enzyme contains as a prosthetic group? (A) Thiamine pyrophosphate (B) Biotin (C) NAD+ (D) Riboflavin-5-phosphate
Description : Orotic aciduria type I reflects the deficiency of enzymes: (A) Orotate phosphoribosyl transferase and orotidylate decarboxylase (B) Dihydroorotate dehydrogenase (C) Dihydroorotase (D) Carbamoyl phosphate synthetase
Description : A coenzyme present in phosphorylase is (A) NAD (B) Pyridoxal phosphate (C) Thiamin pyrophosphate (D) Coenzyme A
Description : Cocarboxylase is (A) Thiamine pyrophosphate (B) Pyridoxal phosphate (C) Biotin (D) CoA
Description : All of the following are required for synthesis of alanine except (A) Pyruvate (B) α-ketoglutarate (C) Glutamate (D) Pyridoxal phosphate
Description : The mechanism of synthesis of DNA and RNA are similar in all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is 5’ → 3’ (D) They require a primer
Description : The mechanism of synthesis of DNA and RNA are similar to all the following ways except (A) They involve release of pyrophosphate from each nucleotide added (B) They require activated nucleotide precursor and Mg2+ (C) The direction of synthesis is (D) They require a primer
Description : Which one of the following statements correctly describes eukaryotic DNA? (A) They involve release of pyrophosphate from each nucleotide precussor and Mg2+ (B) The direction of synthesis is (C) They require a primer 5’→ 3’ (D) None of these
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 : Methotrexate blocks the synthesis of thymidine monophosphate by inhibiting the activity of the enzyme: (A) Dihydrofolate reductase (B) Orotate phosphoribosyl transferase (C) Ribonucleotide reductase (D) Dihydroorotase
Description : All of the following can be formed from pro-opiomelanocortin except (A) α-and β-MSH (B) β-and γ-Lipotropins (C) α-and β-Endorphins(D) FSH
Description : Two molecules of vitamin A can be formed from 1 molecule of (A) α-Carotene (B) β-Carotene (C) γ-Carotene (D) All of these
Description : Glucose-6-phosphate dehydrogenase is induced by (A) 6-Phosphogluconolactone (B) Glucose-6-phosphate (C) Ribose-5-phosphate (D) Insulin
Description : Pentosuria is a rare hereditary disease is characterized by increased urinary excretion of (A) L-xylulose (B) Xylitol (C) Xylulose 5-phosphate (D) Ribose 5-phosphate
Description : Xylulose-5-phosphate serves as a donar of active glycolaldehyde, the acceptor is (A) Erythrose 4-phosphate (B) Ribose 5-phosphate (C) Glyceraldehyde 3-phosphate (D) Sedoheptulose 7-phosphate
Description : In pentose phosphate pathway, D-ribulose5-phosphate is converted to D-ribose-5- phosphate by the enzyme: (A) Fumarase (B) Ketoisomerase (C) G-6-PD (D) Epimerase
Description : In RNA, apart from ribose and phosphate, all following are present except (A) Adenine (B) Guanine (C) Thymine (D) Cytosine
Description : A nucleotide is formed of (a) purine, pyrimidine and phosphate (b) purine, sugar and phosphate (c) nitrogen base, sugar and phosphate (d) pyrimidine, sugar and phosphate
Last Answer : (c) nitrogen base, sugar and phosphate
Description : Cytosolic and mitochondrial carbamoyl phosphate synthetase have the following similarity: (A) Both use ammonia as a substance (B) Both provide carbamoyl phosphate for urea synthesis (C) Both require N-acetylglutamate as an activator (D) Both are allosteric enzymes
Description : Ring closure of formimidoimidazole carboxamide ribosyl-5-phosphate yields the first purine nucleotide: (A) AMP (B) IMP (C) XMP (D) GMP
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 : A radioactive substance does not emit (A) α-ray (B) Proton (C) Position (D) β-ray
Last Answer : (B) Proton