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 : 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
Last Answer : Answer : A
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
Description : Since the pK values for aspartic acid are 2.0, 3.9 and 10.0, it follows that the isoelectric (pH) is (A) 3.0 (B) 3.9 (C) 5.9 (D) 6.0
Last Answer : (A) 3.0
Description : Substrate concentration at which an enzyme attains half its maximum velocity is (A) Threshold value (B) Michaelis-Menton constant (C) Concentration level (D) None of these
Last Answer : Answer : B
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 : 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 : 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
Last Answer : Answer : C
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 : 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 : 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 : The pH at which an enzyme has maximum activity is known as (A) Isoelectric pH (B) Optimum pH (C) Low pH (D) High pH
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 : In enzyme assays, all the following are kept constant except (A) Substrate concentration (B) Enzyme concentration (C) pH (D) Temperature
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
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 : The catalytic efficiency of two different enzymes can be compared by the (a) formation of the product (b) pH of optimum value (c) Km value (d) molecular size of the enzyme.
Last Answer : (c) Km value
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 : 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 : In competitive enzyme activity inhibition (A) The structure of inhibitor generally resembles that of the substrate (B) Inhibitor decreases apparent Km (C) Km remains unaffective (E) Inhibitor decreases Vmax without affecting Km
Description : The amino acid which has a pK near 4 and thus is negatively charged at pH 7 is (A) Alanine (B) Glutamic acid (C) Glutamine (D) Aspargine
Description : Amino acids excepting histidine are not good buffering agents in cell because (A) They exist as zwitter ions (B) Their pk and not in the physiological pH of a cell (C) Only Histidine has pk of its R group at 6.0 unlike the others which have at a different pH (D) None of these
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 : 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 : Michaelis – Menten equation is used to explain the effect of substrate concentration on (A) Carbohydrate (B) Enzyme (C) Lipid (D) Protein
Description : Isoelectric pH is that pH at which protein is electrically: (A) Neutral (B) Anionic (C) Cationic (D) None of these
Description : This technique takes the advantage of the fact that each protein has different pH at which it is electrically neutral i.e., its isoelectric pH: (A) Isoelectric focussing (B) Immunoel Ectro Phoresis (C) Chromatography (D) HPLC
Description : Isoelectric pH of an amino acid is that pH at which it has a (A) Positive charge (B) Negative charge (C) Nil net charge (D) None of these
Description : Isoelectric pH of an amino acid is that pH at which it has a (A) Positive charge (B) Negative charge (C) No charge (D) None of these
Description : In the genetic disorder of cystinuria, the patient excretes large quantities of cystine in their urine and its low solubility causes crystalline cystine to precipitate as stones in kidneys. The remedy ... C) NaHCO3 prevents stone formation by hydrolysis of cystine to cysteine (D) None of these
Description : Isoelectric pH of an amino acid is that pH at which it has a (A) Positive charge (B) Negative charge (C) No net charge (D) All of these
Description : At a pH below the isoelectric point, an amino acid exists as (A) Cation (B) Anion (C) Zwitterion (D) Undissociated molecule
Description : At isoelectric pH, an amino acid exists as (A) Anion (B) Cation (C) Zwitterion (D) None of these
Description : pH (isoelectric pH) of alanine is (A) 6.02 (B) 6.6 (C) 6.8 (D) 7.2
Last Answer : (A) 6.02
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 : Which one of the following statements is incorrect? (a) The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex. (b) The presence of the competitive inhibitor ... . (d) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.
Last Answer : (b) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate
Description : Explain the process of digestion if a student puts a plain cracker in their mouth, chews it, and holds the mush in their mouth. Mention the pH, temperature, enzyme, substrate and products. ?
Last Answer : Part of the human body
Description : What is the effect of substrate concentration on enzyme activity? -Biology
Last Answer : answer:
Description : Concentration of substrate on enzyme activity. -Biology
Description : In competitive inhibition of enzyme action (A) The apparent Km is decreased (B) The apparent Km is increased (C) Vmax is decreased (D) Apparent concentration of enzyme molecules decreased
Description : In non-competitive enzyme action (A) Vmax is increased (B) Apparent km is increased (C) Apparent km is decreased (D) Concentration of active enzyme molecule is reduced
Description : In reversible non-competitive enzyme activity inhibition (A) Vmax is increased (B) Km is increased (C) Km is decreased (D) Concentration of active enzyme is reduced
Description : Factors affecting enzyme activity: (A) Concentration (B) pH (C) Temperature (D) All of these
Description : The isoelectric point of a protein is (a) the pH at which the protein molecule has no charges on its surface. (b) the pH at which a protein in solution has an equal number of positive and negative charges. (c) the electric charge under isothermal conditions. (b) None of these
Last Answer : the pH at which a protein in solution has an equal number of positive and negative charges
Description : The pH at which the amino acid shows no tendency to migrate when placed in an electric field is known as its : (a) Isoelectric point (b) Dipole moment (c) Iodine number (d) Wavelength
Last Answer : Isoelectric point
Description : Refractive index of a petrofuel which is the ratio of velocity of light in air to its velocity in the petrofuel gives an indication if its (A) Molecular weight (B) Aromatics content (C) Both ‘a’ & ‘b’ (D) Neither ‘a’ nor ‘b’
Last Answer : (C) Both ‘a’ & ‘b