AQA GCSE Biology Paper 1 Practice Exam 2026 - Free GCSE Biology Practice Questions and Revision Guide

The formula for calculating the rate of reaction in the context of enzyme activity is typically expressed as the amount of product formed or substrate used per unit of time. In the case of option B, the equation shows that the rate is calculated by taking a constant (like 1000, which could represent a unit conversion factor such as milliseconds to seconds) and dividing it by the time taken for the reaction to occur.

This means that if you increase the time, the rate decreases since there is more time for the reaction to take place which typically corresponds to a smaller rate value when being calculated in this format. By using this formula, one can determine how quickly an enzyme operates under specific conditions, which is crucial for understanding enzyme kinetics and the efficiency of enzyme activity.

In contrast, the other options do not accurately represent the typical measures of enzyme activity with respect to time and amount produced or consumed. They either provide unrelated or inaccurately structured relationships that do not align with standard biochemical practices. For example, dividing a constant by time emphasizes the inverse relationship between time and rate, an important aspect of measuring reaction performance.