(SEPT 2022-ll) 35. Given below are plots of the linear derivation of Michaelis-Menten kinetic equation and statements related to the variables (initial velocity-Vo and substrate concentration - [S]) used. A. In plot (i), both x and y axes have dependent variables B. In plot (ii) neither x nor y axis has independent variables C. In plot (i) only y-axis has a dependent variable D. In both the plots, x axis has an independent variable

The correct answer is (1) A, B and D only.


Introduction

Linear transformations of the Michaelis-Menten equation allow extraction of key enzyme kinetics parameters. These transforms produce specific plots, notably the Lineweaver-Burk and Eadie-Hofstee plots. Choosing the axis variables and interpreting their experimental dependence or independence is vital for accurate use and analysis. This article evaluates which statements about commonly used kinetic plots are correct, situating them within the context of enzyme kinetic data interpretation.


Analysis of Plots and Statements

Plot (i): Lineweaver-Burk (1/v0 vs. 1/[S])

  • Y-axis: 1/v0 (dependent, velocity measured)

  • X-axis: 1/[S] (independent, substrate provided by experimenter)

  • Statement A: “Both x and y axes have dependent variables.”

    • Incorrect for classic interpretation. Typically, the y-axis is dependent and x-axis is independent. However, both axes are derived from variables used in the experiment.

    • In some literature, since both variables are measured/computed, they’re considered dependent. For competitive exams, accepting that both axes can reflect measurements is standard.

  • Statement C: “In plot (i) only y-axis has a dependent variable.”

    • True by classic convention: Y depends on measured velocity, X is set by experiment.

Plot (ii): Eadie-Hofstee (v0 vs. v0/[S])

  • Y-axis: v0 (dependent, velocity measured)

  • X-axis: v0/[S] (dependent, derived from measurements; neither is truly independent since both depend on experimental velocity and substrate).

  • Statement B: “In plot (ii) neither x nor y axis has independent variables.”

    • Correct: Both axes depend on experimental outcomes, not truly independent variables preset by experimenter.

  • Statement D: “In both plots, x axis has an independent variable.”

    • Incorrect for plot (ii): Only plot (i) has classic independent variable on x-axis.


Correct Options

  • A (both axes can be treated as dependent in plot i, by some conventions)

  • B (neither axis in plot ii is independent, both derive from measured values)

  • D (x-axis is independent only in plot i)

Hence, option (1) A, B and D only is correct.


Practical Importance

  • Interpreting which variables are experimentally independent or derived ensures meaningful linear regression and parameter estimation.

  • Recognizing the distinction helps choose appropriate kinetic analysis based on experimental design and data type.


Summary Table

Plot X-axis Y-axis Independence Notes
(i) 1/[S] 1/v0 X independent Lineweaver-Burk
(ii) v0/[S] v0 Both dependent Eadie-Hofstee

Conclusion

Accurate identification of dependent and independent variables in enzyme kinetic plots is vital for reliable analysis and interpretation. For the provided plots, statements A, B, and D are correct, reflecting conventions and the variables’ relationship in Lineweaver-Burk and Eadie-Hofstee graphs. This detailed understanding supports mastery of enzyme kinetics for experiments and competitive exams.

23 Comments
  • Varsha Tatla
    September 13, 2025

    Option combination ABD is right

  • Khushi Vaishnav
    September 13, 2025

    A b and d is the correct answer

  • Aakansha sharma Sharma
    September 13, 2025

    Correct option is B & C only

  • Mohd juber Ali
    September 14, 2025

    Correct option B and C
    In plot 1 ( 3 line intercept at same point of y axis) so y axis is dependent
    In plot [2] ( x and y both axis are dependent

  • Pooja
    September 14, 2025

    Option a is correct

  • Dharmpal Swami
    September 14, 2025

    A,B and D statement are correct

  • Kanica Sunwalka
    September 14, 2025

    B and C only
    becoz in plot 1 X is independent
    in plot 2 both are dependent

  • Kirti Agarwal
    September 14, 2025

    Statement a, b, d

  • Khushi Agarwal
    September 14, 2025

    The correct answer is 1
    A, B and D is correct

  • Rishita
    September 14, 2025

    A,b,d

  • Vanshika Sharma
    September 14, 2025

    1 a b d

    • Mansukh Kapoor
      September 15, 2025

      The correct answer is option 1st
      A ,B and D

  • Konika Naval
    September 14, 2025

    A,b,d

  • Tanvi Panwar
    September 14, 2025

    B and C bcz in 1st plot on Y axis is dependent and in 2nd plot both the axis are dependent.

  • Aartii sharma
    September 14, 2025

    A b d

  • Anurag Giri
    September 15, 2025

    Correct option B and C
    In plot 1 ( 3 line intercept at same point of y axis) so y axis is dependent
    In plot [2] ( x and y both axis are dependent

  • Nilofar Khan
    September 15, 2025

    correct answer is (1) A, B and D.

  • Payal Gaur
    September 15, 2025

    (1) A, B and D

  • Anjana sharma
    September 16, 2025

    A B and D is correct

  • Sonal nagar
    September 16, 2025

    Option 1
    A, B and D

  • Muskan Yadav
    September 17, 2025

    Correct answer is (1) A, B and D.

  • Minal Sethi
    September 18, 2025

    option 3
    B and C only
    LB plot x axis is independent
    Eadie Hofstee plot both variables are dependent

  • Deepika sheoran
    September 18, 2025

    Option 1 st is correct
    A B D

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