Description : The following reaction is characteristic of what type of enzymes? 2H2O2 → 2H2O + O2 (A) Peroxides (B) Catalase (C) Dehydrogenase (D) Copper containing oxidases
Last Answer : Answer : B
Description : A deficiency of copper effects the formation of normal collagen by reducing the activity of which of the following enzyme? (A) Prolyl hydroxylase (B) Lysyl oxidase (C) Lysyl hydroxylase (D) Glucosyl transferase
Description : Ehlers-Danlos syndrome characterized by hypermobile joints and skin abnormalities is due to (A) Abnormality in gene for procollagen (B) Deficiency of lysyl oxidase (C) Deficiency of prolyl hydroxylase (D) Deficiency of lysyl hydroxylase
Last Answer : Answer : A
Description : Translocation of the newly formed peptidyl tRNA at the A site into the empty P site involves (A) EF-II, GTP (B) EF-I, GTP (C) EF-I, GDP (D) Peptidyl transferase, GTP
Description : All the oxidases contain a metal which is (A) Copper (B) FAD (C) Manganese (D) None of these
Description : Molybdenum is a constituent of (A) Hydroxylases (B) Oxidases (C) Transaminases (D) Transferases
Description : Acute pancreatitis is characterised by (A) Lack of synthesis of zymogen enzymes (B) Continuous release of zymogen enzymes into the gut (C) Premature activation of zymogen enzymes (D) Inactivation of zymogen enzymes
Last Answer : Answer : C
Description : The mechanism of antibacterial action of tetracycline involves (a) Binding to a component of the 50S ribosomal subunit (b) Inhibition of translocase activity (c) Blockade of binding of ... (d) Selective inhibition of ribosomal peptidyl transferases (e) Inhibition of DNA-dependent RNA polymerase
Last Answer : Ans: C
Description : Erythromycin binds to 50 S ribosomal sub unit and (A) Inhibits binding of amino acyl tRNA (B) Inhibits Peptidyl transferase activity (C) Inhibits translocation (D) Causes premature chain termination
Description : Peptidyl transferase activity of 50 S ribosomal subunits is inhibited by (A) Rifampicin (B) Cycloheximide (C) Chloramphenicol (D) Erythromycin
Description : After formation of a peptide bond, mRNA is translocated along the ribosome by (A) eEF-1 and GTP (B) eEF-2 and GTP (C) Peptidyl transferase and GTP (D) Peptidyl transferase and ATP
Description : Peptidyl transferase activity is present in (A) 40 S ribosomal subunit (B) 60 S ribosomal subunit (C) eEF-2 (D) Amino acyl tRNA
Description : Peptidyl transferase activity is located in (A) Elongation factor (B) A charged tRNA molecule (C) Ribosomal protein (D) A soluble cytosolic protein
Description : Erythromycin acts on ribosomes and inhibit (A) Formation of initiation complex (B) Binding of aminoacyl tRNA (C) Peptidyl transferase activity (D) Translocation
Last Answer : Answer : D
Description : Streptomycin prevents synthesis of polypeptide by (A) Inhibiting initiation process (B) Releasing premature polypeptide (C) Inhibiting peptidyl transferase activity (D) Inhibiting translocation
Description : In prokaryotes, chloramphenicol (A) Causes premature release of the polypeptide chain (B) Causes misreading of the mRNA (C) Depolymerises DNA (D) Inhibits peptidyl transferase activity
Description : The nucleophilic attack on the esterified carboxyl group of the peptidyl-tRNA occupying the P site and the α-amino group of the new amino acyl tRNA, the number of ATP required by the amino acid on the charged tRNA is (A) Zero (B) One (C) Two (D) Four
Description : The α-amino group of the new amino acyl tRNA in the A site carries out a nucleophilic attack on the esterified carboxyl group of the peptidyl tRNA occupying the P site. This reaction is catalysed by (A) DNA polymerase (B) RNA polymerase (C) Peptidyl transferase (D) DNA ligase
Description : The enzyme amino acyl tRNA synthetase is involved in (A) Dissociation of discharged tRNA from 80S ribosome (B) Charging of tRNA with specific amino acids (C) Termination of protein synthesis (D) Nucleophilic attack on esterified carboxyl group of peptidyl tRNA
Description : The anaesthetic action of thiopentone sodium is characterised by: A. Good muscle relaxation B. Poor analgesia C. Sensitization of heart to adrenaline D. No postoperative residual CNS depression
Last Answer : B. Poor analgesia
Description : Which of the following step of translation does not consume a high energy phosphate bond? (a) Peptidyl transferase reaction (b) Aminoacyl tRNA binding to A-site (c) Translocation (d) Amino acid activation
Last Answer : (b) Aminoacyl tRNA binding to A-site
Last Answer : (a) Peptidyl transferase reaction
Description : Which of the following molecule catalyzes the transpeptidation reaction? A.RNA polymerase B.Peptidyl transferase C.DNA ligase D.DNA polymerase
Last Answer : B.Peptidyl transferase
Description : Which binding is inhibited by pactamycin? A- Aminoacyl-tRNA to the A-site of 30S subunit B- Initiator-tRNA to 30S/40S initiation complexes C- Peptidyl t-RNA to the 50S subunit D- Formation of peptide bond in P site
Last Answer : Initiator-tRNA to 30S/40S initiation complexes
Description : Peptidyl transferase a) Is a 23s rRNA b) forms peptide bonds c) component of ribosome d) all the three
Last Answer : d) all the three
Description : Select the antibiotic which inhibits bacterial protein synthesis by interfering with translocation of elongating peptide chain from acceptor site back to the peptidyl site of the ribosome so that ... chain is prematurely terminated: A. Chloramphenicol B. Erythromycin C. Tetracycline D. Streptomycin
Last Answer : B. Erythromycin
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 : Which of the following statements is true? (A) Enzymes have names ending ase (B) Enzymes are highly specific in their action (C) Enzymes are living organisms (D) Enzymes get activated on heating
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 : The glycerol for fatty acid esterification in adipocytes is (A) For the most part, derived from glucose (B) Obtained primarily from phosphorylation of glycerol by glycerol kinase (C) Formed from gluconeogenesis (D) Formed from glycogenolysis ENZYMES 153
Description : Brown adipose tissue is (A) A prominent tissue in human (B) Characterised by high content of mitochondria (C) Associated with high activity of ATP synthase (D) Characterised by low content of cytochromes
Description : Which of the following statements is not correct? (a) Lysosomes are formed by the process of packaging in the endoplasmic reticulum. (b) Lysosomes have numerous hydrolytic enzymes. (c) The hydrolytic enzymes of lysosomes are active under acidic pH. (d) Lysosomes are membrane-bound structures.
Last Answer : (a) Lysosomes are formed by the process of packaging in the endoplasmic reticulum.
Description : Lysolecithin is formed from lecithin by the action of (A) Phospholipase A1 (B) Phospholipase A2 (C) Phospholipase C (D) Phospholipase D
Description : All the following statements about pepsin are correct except (A) It is smaller than pepsinogen (B) It is formed by the action of HCl on its precursor (C) Its optimum pH is 1.0–2.0 (D) It hydrolyses the C-terminal and N-terminal peptide bonds of proteins
Description : Fructose-2, 6-biphosphate is formed by the action of (A) Phosphofructokinase-1 (B) Phosphofructokinase-2 (C) Fructose biphosphate isomerase (D) Fructose-1, 6-biphosphatase
Last Answer : B
Description : $ Enzymes are special types of proteins. ! Those substances which interfere with the action of enzymes are called inhibitors.
Last Answer : $ Enzymes are special types of proteins. ! Those substances which interfere with the action of enzymes are ... wrong D. If both As and R are wrong.
Description : Assetion: Restriction enzymes cut the strand 27 of DNA to produce sticky ends Reason : Stickiness of the ends faciliates the action of the enzyme DNA
Last Answer : Assetion: Restriction enzymes cut the strand 27 of DNA to produce sticky ends Reason : Stickiness of ... D. If both assertion and reason are false
Description : During the process of isolation of DNA, chilled ethanol is added to (a) precipitate DNA (b) break open the cell to release DNA (c) facilitate action of restriction enzymes (d) remove proteins such as histones.
Last Answer : a) precipitate DNA
Description : Restriction endonucleases are enzymes which (a) make cuts at specific positions within the DNA molecule (b) recognize a specific nucleotide sequence for binding of DNA ligase (c) restrict the action of the enzyme DNA polymerase (d) remove nucleotides from the ends of the DNA molecule
Last Answer : (a) make cuts at specific positions within the DNA molecule
Description : Which of the following organelles contain enzymes that have digestive action? (a) Ribosomes (b) Polysomes (c) Plastids (d) Lysosomes
Last Answer : (d) Lysosomes
Description : Viropexis takes place in the phagocytic vacuoles and is due to the action of Enzymes A- DNA gyrase B- lysosomal protease C- lysosomal lipase D- all of these
Last Answer : lysosomal protease
Description : Trichloroacetic acid, a strong acid, has been used by dentists for chemical cautery of hypertrophic tissue and aphthous ulcers; its mechanism of action is, BOUCHERS P 194 A. Thermodynamic ... Activation of tissue enzymes C. Osmotic pressure D. Protein precipitation (PPT) E. Neutralization
Last Answer : D. Protein precipitation (PPT)
Description : Suppuration is mainly the result of the combined action of four factors; which of the following is not one of these factors?CHECK A. Necrosis B. Presence of lymphocytes C. Collection of neutrophils D. Accumulation of tissue fluid E. Autolysis by proteolytic enzymes
Last Answer : B. Presence of lymphocytes
Description : Tolerance does not develop to the vasodilator action of sodium nitroprusside while it develops to glyceryl trinitrate because: A. Intact sod. nitroprusside molecule acts like nitric oxide B. Enzymes which ... a long duration of action D. Sod. nitroprusside has additional K+ channel opening action
Last Answer : B. Enzymes which generate nitric oxide from nitroprusside are different
Description : Organic nitrates have predominantly venodilator action because: A. They are selectively concentrated in veins B. Veins express larger quantities of enzymes that generate nitric oxide from nitrates C. Venous smooth muscle has greater capacity to relax D. All of the above are correct
Last Answer : B. Veins express larger quantities of enzymes that generate nitric oxide from nitrates
Description : The most important mechanism of antiinflammatory action of glucocorticoids is: A. Inhibition of lysosomal enzymes B. Restriction of recruitment of inflammatory cells at the site of inflammation C. Antagonism of action of interleukins D. Suppression of complement function
Last Answer : B. Restriction of recruitment of inflammatory cells at the site of inflammation
Description : 20. Which one of the following statements is incorrect about enzyme catalysis? (1) Enzymes are least reactive at optimum temperature (2) Enzymes are mostly proteinous in nature (3) Enzyme action is specific (4) Enzymes are denaturated by ultraviolet rays and at high temperature
Last Answer : Enzymes are least reactive at optimum temperature
Description : The process of self-digestion of selective non-functional organelles by a cell through the action of enzymes originating within the cell is referred to as (A) Pinocytosis (B) Endocytosis (C) Autophagy (D) Cytotoxicity
Last Answer : (C) Autophagy
Description : What is the term given to enzymes whose action is modulated by binding of a molecule to a site other than the active site?
Last Answer : ANSWER: ALLOSTERIC ENZYMES
Description : $ The enzymes which joins short pieces DNA in the laggins strand is called ligase. ! Lagging strand and leading strand are formed due to replication f
Last Answer : $ The enzymes which joins short pieces DNA in the laggins strand is called ligase. ! Lagging strand and ... wrong D. If both As and R are wrong.