Description : The Michaelis constant, Km is (A) Numerically equal to ½ Vmax (B) Dependent on the enzyme concentration (C) Independent of pH (D) Numerically equal to the substrate concentration that gives half maximal velocity
Last Answer : Answer : D
Description : Michaelis – Menten equation is used to explain the effect of substrate concentration on (A) Carbohydrate (B) Enzyme (C) Lipid (D) Protein
Last Answer : Answer : B
Description : Velocity maximum for an enzyme at half the substrate concentration gives (A) The molecular weight of the enzyme (B) Km value (C) Isoelectric pH (D) Pk value
Description : A sigmoidal plot of substrate concentration ([S]) verses reaction velocity (V) may indicate (A) Michaelis-Menten kinetics (B) Co-operative binding (C) Competitive inhibition (D) Non-competitive inhibition
Description : From the L ineweaver-Burk p lot of Michaelis-Menten equation, Km and Vmax can be determined when V is the reaction velocity at substrate concentration S, the X-axis experimental data are expressed as (A) 1/V (B) V (C) 1/S (D) S
Last Answer : Answer : C
Description : When [s] is equal to Km, which of the following conditions exist? (A) Half the enzyme molecules are bound to substrate (B) The velocity of the reaction is equal to Vmax (C) The velocity of the reaction is independent of substrate concentration (D) Enzyme is completely saturated with substrate
Last Answer : Answer : A
Description : The rate of an enzyme catalyzed reaction was measured using several substrate concentrations that were much lower than Km, the dependence of reaction velocity on substrate concentration can best be ... constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration
Description : In enzyme kinetics Km implies (A) The substrate concentration that gives one half Vmax (B) The dissocation constant for the enzyme substrate comples (C) Concentration of enzyme (D) Half of the substrate concentration required to achieve Vmax
Description : If the substrate concentration is much below the km of the enzyme, the velocity of the reaction is (A) Directly proportional to substrate concentration (B) Not affected by enzyme concentration (C) Nearly equal to Vmax (D) Inversely proportional to substrate concentration
Description : In enzyme kinetics Vmax reflects (A) The amount of an active enzyme (B) Substrate concentration (C) Half the substrate concentration (D) Enzyme substrate complex
Description : In enzyme assays, all the following are kept constant except (A) Substrate concentration (B) Enzyme concentration (C) pH (D) Temperature
Description : Which one of the following statements is not characteristic of allosteric enzymes? (A) They frequently catalyze a committed step early in a metabolic pathway (B) They are often composed of subunits (C) They follow Michaelis-Menten kinetics (D) They frequently show cooperativity for substrate binding
Description : When the velocity of an enzymatic reaction equals Vmax, substrate concentration is (A) Half of Km (B) Equal to Km (C) Twice the Km (D) Far above the Km
Description : Different isoenzymes of an enzyme have the same (A) Amino acid sequence (B) Michaelis constant (C) Catalytic activity (D) All of these
Description : Km value of enzyme is substrate concentration at (A) ½ Vmax (B) 2 Vmax (C) ½ Vmax (D) 4 Vmax
Description : In reversible non-competitive enzyme activity inhibition (A) Inhibitor bears structural resemblance to substrate (B) Inhibitor lowers the maximum velocity attainable with a given amount of enzyme (C) Km is increased (D) Km is decreased
Description : Define Michaelis constant of an enzyme. -Biology
Last Answer : answer:
Description : Feedback term refers to (A) Effect of substrate on rate of enzymatic reaction (B) Effect of end product on rate reaction (C) Effect of enzyme concentration on rate of reaction (D) Effect of external compound on rate of reaction
Description : Enzymes activity is controlled by (A) pH of the solution (B) Temperature (C) Concentration of the enzyme (D) Concentration of the substrate (E) All of these
Description : The Michaehis-Menten hypothesis: (A) Postulates the formation of an enzyme substrate complex (B) Enables us to calculate the isoelectric point of an enzyme (C) States that the ... independent of substrate concentration (D) States that the reaction rate is proportional to substrate concentration
Description : Competitive inhibition can be relieved by raising the (A) Enzyme concentration (B) Substrate concentration (C) Inhibitor concentration (D) None of these
Description : Lineweaver – Burk double reciprocal plot is related to (A) Substrate concentration (B) Enzyme activity (C) Temperature (D) Both (A) and (B) ENZYMES 145
Description : Kinetics of an allosteric enzyme are explained by (A) Michaelis-Menten equation (B) Lineweaver-Burk plot (C) Hill plot (D) All of these
Description : If all the enzymes, intermediates and cofactors of the citric acid cycle as well as an excess of the starting substrate acetylCoA are present and functional in an organelle free solution at the appropriate ... oxygen (B) Half life of enzyme (C) Turnover of intermediates (D) Reduction of cofactors
Description : Threshold Limit Value (TLV) is the maximum allowable concentration (i.e. safe limit) of pollutants in air. Safe limit for SO2 in air is __________ ppm. (A) 5 (B) 500 (C) 1000 (D) 2000
Last Answer : (A) 5
Description : Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about __________ ppm (parts per million). (A) 0.002 (B) 0.2 (C) 1.2 (D) 4.8
Last Answer : (B) 0.2
Description : What is the effect of substrate concentration on enzyme activity? -Biology
Description : Concentration of substrate on enzyme activity. -Biology
Description : The curve given below shows enzymatic activity in relation to three conditions (pH, temperature and substrate concentration). What do the two axes (X and Y) represent? X-axis ... (b) Temperature Enzyme activity (c) Substrate Enzymatic concentration activity (d) Enzymatic activity Temperature
Last Answer : (b) Temperature Enzyme activity
Description : ........................ studied the kinetics of enzyme catalysis. a. Arrhenius b. Rutherford c. Micheal Faraday d. Michaelis & Menten
Last Answer : d. Michaelis & Menten
Description : Time required for the organism to eliminate 50% the total body burden or tissue concentration of chemical is referred as – (1) Threshold limit time (2) Halftime life (3) Residual-period (4) Half-life period
Last Answer : (4) Half-life period Explanation: Time required for the organism to eliminate 50 per cent of the total body burden or tissue concentration of chemical is referred to as Half Life Period.
Description : Time required for the organism to eliminate 50% the total body burden or tissue concentration of chemical is referred as (1) Threshold limit time (2) Half-time life (3) Residual period (4) Half-life period
Last Answer : Half-life period
Description : What is Michaelis Menten constant? -Biology
Description : The shape of an enzyme and consequently its activity can be reversibly altered from moment to moment by (A) Heat (B) Amino acid substrate (C) Allosteric subunits (D) Sulfur substitutions
Description : Indicate the drug which attains therapeutic antibacterial concentration in the urinary tract but not in other tissues: A. Pefloxacin B. Amikacin C. Nitrofurantoin D. Cephalexin
Last Answer : C. Nitrofurantoin
Description : The acquisition energy by glucose fermentation requires A.substrate-level phosphorylation B.electron transport of electrons from NADH C.long-chain fatty acid oxidation D.the enzyme formic-hydrogen lyase
Last Answer : A.substrate-level phosphorylation
Description : Most of the energy in aerobic respiration of glucose is captured by A- substrate-level phosphorylation B- electron transport of electrons from NADH C- long-chain fatty acid oxidation D- the enzyme formic-hydrogen lyase
Last Answer : electron transport of electrons from NADH
Description : The ratio of enzyme to substrate molecules can be as low as (A) 1 : 100,000 (B) 1 : 500,000 (C) 1 : 10,000 (D) 1 : 1,000
Description : Feedback inhibition of enzyme is influenced by (A) Enzyme (B) External factors (C) End product (D) Substrate
Description : Enzyme inhibition caused by a substance resembling substrate molecule is (A) Competitive inhibition (B) Non-competitive inhibition (C) Feedback inhibition (D) Allosteric inhibition
Description : Combination of apoenzyme and coenzyme produces (A) Prosthetic group (B) Holoenzyme (C) Enzyme substrate complex (D) Enzyme product complex
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 : Feedback inhibition of enzyme action is affected by (A) Enzyme (B) Substrate (C) End products (D) None of these
Description : An enzyme promotes a chemical reaction by (A) Lowering the energy of activation (B) Causing the release of heat which acts as a primer (C) Increasing molecular motion (D) Changing the free energy difference between substrate and product
Description : Lock' and Key' model of enzyme action proposed by Fisher implies that (A) The active site is flexible and adjusts to substrate (B) The active site requires removal of PO4 group ( ... complementary in shape to that of the substrate (D) Substrates change conformation prior to active site interaction
Description : A competitive inhibitor of an enzyme has which of the following properties? (A) It is frequently a feedback inhibitor (B) It becomes covalently attached to an enzyme (C) It decreases the Vmax (D) It interferes with substrate binding to the enzyme
Description : An allosteric enzyme influences the enzyme activity by (A) Competiting for the catalytic site with the substrate (B) Changing the specificity of the enzyme for the substrate (C) Changing the conformation ... binding to a site other than catalytic site (D) Changing the nature of the products formed
Description : If a coenzyme is required in an enzyme reaction, the former usually has the function of (A) Acting as an acceptor for one of the cleavage products of the substrate (B) Enhancing the specificity ... C) Increasing the number of receptor sites of the apo enzyme (D) Activating the substrate ENZYMES 167
Description : A substrate for the enzyme aldolase is (A) galactose-6-phosphate (B) isocitric acid (C) Glucose-1-phosphate (D) Fructose 1, 6 diphosphate
Description : In competitive inhibition, the inhibitor (A) Competes with the enzyme (B) Irreversibly binds with the enzyme (C) Binds with the substrate (D) Competes with the substrate