A Level Biology Practice Exam

What does the temperature coefficient (Q10) measure?

1. a measure of how much the rate of a reaction increases with a 5 °C temperature increase

2. a measure of how much the rate of a reaction decreases with increasing temperatures

3. a measure of how much the rate of a reaction increases with a 10 °C temperature increase

4. a measure of the overall energy of reactants in a chemical reaction

The correct answer is: a measure of how much the rate of a reaction increases with a 10 °C temperature increase

The temperature coefficient, commonly denoted as Q10, specifically measures how much the rate of a biochemical reaction increases when the temperature is raised by 10 °C. This coefficient is significant in biological systems because it provides insight into the temperature sensitivity of enzymatic reactions and metabolic processes. Typically, a Q10 value of around 2 to 3 is observed, indicating that the reaction rate can double or triple with every 10 °C rise in temperature. This temperature dependence is crucial for understanding physiological adaptations, enzyme kinetics, and overall metabolic rates in living organisms. In the context of this question, the correct choice accurately reflects this definition, emphasizing the focus on the increase in reaction rate with a 10 °C increase in temperature, rather than a 5 °C increase, as stated in another choice, or incorrect notions about energy levels of reactants.