Question

1. you are looking at a lineweaver - burk plot. the lines for the normal reaction and the inhibited reaction both cross the -axis at the exact same point. what does this te you? a. the reaction has stopped b. it is non - competitive inhibition c. it is competitive inhibition d. the $k_m$ has not changed

Explanation:

A Lineweaver-Burk plot is a double reciprocal plot of enzyme kinetics, where the x-intercept equals $-\frac{1}{K_m}$. When normal and inhibited reactions share the same x-intercept, their $K_m$ values are identical. This is characteristic of non-competitive inhibition, where the inhibitor binds equally well to free enzyme and enzyme-substrate complex, leaving the enzyme's affinity for substrate ($K_m$) unchanged. Option A is incorrect because the plot shows ongoing reaction kinetics, not a stopped reaction. Option C is wrong because competitive inhibition changes $K_m$, shifting the x-intercept. Option D is a true observation but is a consequence of the inhibition type described in B, which is the more complete conclusion.

Answer:

B. It is non-competitive inhibition
D. The $K_m$ has not changed