Biology 9700 · AS & A Level · Factors that affect enzyme action

Factors that affect enzyme action — practice question

In an investigation, an equal concentration of the enzyme phosphorylase was mixed with different concentrations of glucose phosphate and left at $30^\circ\text{C}$. At intervals of $1$ minute, a single drop of the reaction mixture was taken and placed onto a drop of iodine solution on a white tile. The diagram presents the outcomes of this investigation. What accounts for the pattern seen in the results of this investigation?

  • APhosphorylase catalyses a reaction converting glucose phosphate to starch.
  • BThe maximum rate of reaction is reached at $20\,\text{mg dm}^{-3}$ of glucose phosphate.
  • CSubstrate concentration is limiting at concentrations of glucose phosphate $25\,\text{mg dm}^{-3}$ or less.
  • DEnzyme concentration is limiting at concentrations of glucose phosphate $25\,\text{mg dm}^{-3}$ or less.

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