Description : In which of the following types of enzymes an inducer is not required? (A) Inhibited enzyme (B) Cooperative enzyme (C) Allosteric enzyme (D) Constitutive enzyme
Last Answer : Answer : D
Description : Enzymes which are always present in an organism are known as (A) Inducible enzymes (B) Constitutive enzymes (C) Functional enzymes (D) Apoenzymes
Last Answer : Answer : B
Description : A demonstrable inducer is absent in (A) Allosteric enzyme (B) Constitutive enzyme (C) Inhibited enzyme (D) Co-operative enzyme ENZYMES 141
Description : Which of the following genes of the E.coli “Lac operon” codes for a constitutive protein? (A) The ‘a’ gene (B) The ‘i’ gene (C) The ‘c’ gene (D) The ‘z’ gene
Description : The gene of lac operon which has constitutive expression is (A) i (B) c (C) z (D) p
Last Answer : Answer : A
Description : An inducer is absent in the type of enzyme: (A) Allosteric enzyme (B) Constitutive enzyme (C) Co-operative enzyme (D) Isoenzymic enzyme
Description : The transport of proteins out of the cell is termed exocytosis. Which of the following statement(s) is/are true concerning this process? a. Secretory vesicles fuse with the plasma membrane b. ... or a neurotransmitter d. A decrease in cytoplasmic calcium occurs as part of the secretion process
Last Answer : Answer: a, b, c Transport vesicles that bud off the Golgi network carry both material to be secreted from the cell and protein destined to become components of the plasma ... but may also involve generation of diacylglycerol or production of cyclic AMP which activate kinases or phosphatases
Description : The cyclooxygenase isoenzymes COX-1 and COX-2 differ from each other in that (a) They catalyse different pathways in prostanoid biosynthesis (b) COX–1 is inhibited by aspirin but not COX–2 (c) COX–2 is inhibited by ibuprofen but not COX–1 (d) COX–1 is constitutive while COX–2 is inducible
Last Answer : Ans: D
Description : Optical activity is a/an __________ property. (A) Additive (B) Constitutive (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : The cyclooxygenase isoenzymes COX-1 and COX-2 differ from each other in that: A. They catalyse different pathways in prostanoid biosynthesis B. COX-1 is inhibited by aspirin but not COX-2 C. COX-2 is inhibited by ibuprofen but not COX-1 D. COX-1 is constitutive while COX-2 is largely
Last Answer : D. COX-1 is constitutive while COX-2 is largely
Description : Restriction enzymes have been found in (A) Humans (B) Birds (C) Bacteria (D) Bacteriophase
Last Answer : Answer : C
Description : Which of the following is present as a marker in lysosomal enzymes to direct them to their destination? (A) Glucose-6-phosphate (B) Mannose-6-phosphate (C) Galactose-6-phosphate (D) N-Acetyl neuraminic acid
Description : The enzymes encoded by z, y and a genes of lac operon are inducible, and their inducer is (A) Lactose (B) Allo-lactose (C) Catabolite gene activator protein (D) All of these
Description : DNA contains some palindromic sequences which (A) Mark the site for the formation of replication forks (B) Direct DNA polymerase to turn back to replicate the other strand (C) Are recognized by restriction enzymes (D) Are found only in bacterial DNA
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 : All of the following enzymes are unique to purine nucleotide synthesis except (A) PRPP synthetase (B) PRPP glutamyl amido transferase (C) Adenylosuccinate synthetase (D) IMP dehydrogenase
Description : In the pathway of de novo synthesis of purine nucleotides, all the following are allosteric enzymes except (A) PRPP glutamyl amido transferase (B) Adenylosuccinate synthetase (C) IMP dehydrogenase (D) Adenylosuccinase
Description : Ribozymes are (A) Enzymes present in ribosomes (B) Enzymes which combine the ribosomal subunits (C) Enzymes which dissociate (D) Enzymes made up of RNA
Description : Restriction endonucleases (A) Cut RNA chains at specific locations (B) Excise introns from hnRNA (C) Remove Okazaki fragments (D) Act as defensive enzymes to protect the host bacterial DNA from DNA of foreign organisms
Description : In the process of transcription in bacterial cells (A) Initiation requires rho protein (B) RNA polymerase incorporates methylated bases in correct sequence (C) Both the sigma unit and core ... RNA polymerase are required for accurate promotor site binding (D) Primase is necessary for initiation
Description : After termination of the synthesis of RNA molecule, the core enzymes separate from the DNA template. The core enzymes then recognize a promoter at which the synthesis of a new RNA molecule commences, with the assistance of (A) Rho (ρ) factor (B) δ factor (C) β factor (D) σ factor
Description : An autosomal recessive disorder, xanthinuria is due to deficiency of the enzymes: (A) Adenosine deaminase (B) Xanthine oxidase (C) HGPRTase (D) Transaminase
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 substrate for enzymes of pyrimidine nucleotide biosynthesis is (A) Allopurinol (B) Tetracylin (C) Chloramphenicol (D) Puromycin
Description : In the biosynthesis of cortiol, the sequence of enzymes involved is (A) Hydroxylase–dehydrogenase + isomerase – hydroxylase (B) Dehydrogenase–hydroxylase–isomerase (C) Hydroxylase–lyase–dehydrogenase isomerase (D) Isomerase–lyase–hydroxylase–dehydrogenase
Description : Hormones (A) Act as coenzyme (B) Act as enzyme (C) Influence synthesis of enzymes (D) Belong to B-complex group
Description : Hinge region, the region of Ig molecule which is flexible and more exposed to enzymes is the (A) Region between first and second constant regions of H chain (domains CH1 and CH2) (B) Region between second and ... H chain (CH2 and CH3) (C) Variable regions of H chain (D) Variable regions of L chain
Description : In conversion of lactic acid to glucose, three reactions of glycolytic pathway are circumvented, which of the following enzymes do not participate? (A) Pyruvate carboxylase (B) Phosphoenol pyruvate carboxy kinase (C) Pyruvate kinase (D) Glucose-6-phosphatase
Description : A mitochondrial marker enzyme is (A) Aldolase (B) Amylase (C) Succinic dehydrogenase (D) Pyruvate dehydrogenase ENZYMES 175
Description : The enzymes present in the membrane of mitochondria are (A) Flavoproteins and cytochromes (B) Fumarase and lipase (C) Enolase and catalase (D) Hexokinase and zymase
Description : Enzymes functional in cell or mitochondria are (A) Endoenzymes (B) Exoenzymes (C) Apoenzymes (D) Holoenzymes
Description : In cell, digestive enzymes are found mainly in (A) Vacuoles (B) Lysosomes (C) Ribosomes (D) Lomasomes
Description : Out of the total enzymes present in a cell, a mitochondrion alone has (A) 4% (B) 70% (C) 95% (D) 50%
Description : The best example of extracellular enzymes (exoenzyme) is (A) Nucleases (B) Digestive enzymes (C) Succinic dehydrogenase (D) None of these
Description : The fruit when kept is open, tastes bitter after 2 hours because of (A) Loss of water from juice (B) Decreased concentration of fructose in juice (C) Fermentation by yeast (D) Contamination by bacterial enzymes
Description : Who got Nobel Prize in 1978 for working on enzymes? (A) Koshland (B) Arber and Nathans (C) Nass and Nass (D) H.G. Khorana
Description : Which is not true about inorganic catalysts and enzymes? (A) They are specific (B) Inorganic catalysts require specific not needed by enzymes (C) They are sensitive to pH (D) They speed up the rate of chemical reaction
Description : Coenzyme is (A) Often a vitamin (B) Always an inorganic compound (C) Always a protein (D) Often a metal ENZYMES 173
Description : Template/lock and key theory of enzyme action is supported by (A) Enzymes speed up reaction (B) Enzymes occur in living beings and speed up certain reactions (C) Enzymes determine the direction of reaction (D) Compounds similar to substrate inhibit enzyme activity
Description : Dry seeds endure higher temperature than germinating seeds as (A) Hydration is essential for making enzymes sensitive to temperature (B) Dry seeds have a hard covering (C) Dry seeds have more reserve food (D) Seedlings are tender
Description : Enzymes, vitamins and hormones are common in (A) Being proteinaceous (B) Being synthesized in the body of organisms (C) Enhancing oxidative metabolism (D) Regulating metabolism
Description : Enzymes are different from catalysts in (A) Being proteinaceous (B) Not used up in reaction (C) Functional at high temperature (D) Having high rate of diffusion
Description : In plants, enzymes occur in (A) Flowers only (B) Leaves only (C) All living cells (D) Storage organs only
Description : Enzymes are required in traces because they (A) Have high turnover number (B) Remain unused at the end of reaction and are re used (C) Show cascade effect (D) All correct
Description : Who suggested that enzymes are proteinaceous? (A) Buchner (B) Kuhne (C) Sumner (D) Pasteur
Description : IUB had divided enzymes into how many classes? (A) 6 (B) 5 (C) 8 (D) 4
Description : Allosteric enzymes contain (A) Multiple subunits (B) Single chain (C) Two chains (D) Three chains
Description : The active site of an enzyme is formed by a few of the enzymes: (A) R groups of the amino acids (B) Amino groups of the amino acids (C) Carboxyl group of the amino acids (D) Exposed sulfur bonds
Description : Enzymes increases the rate of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction
Description : In which of the following types of enzymes, water may be added to a C—C double bond without breaking the bond? (A) Hydrolase (B) Hydratase (C) Hydroxylase (D) Oxygenase