Q10 prelecture PDF

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BIO120: Temperature Sensitivity Prelecture

Q10 is a measure of temperature sensitivity of an enzymatic reaction or a physiological process due to an increase of 10°C. Most Q10 values are around between 2 and 3 and this reflects a doubling or tripling of the rate with a 10°C rise in temperature. The equation for Q10 that we will be using is shown in the graph below. R T is that rate of a reaction at some temperature T. RT-10 is the rate of the same reaction at a temperature 10°C below T. If the temperature changes by something other than 10°C, then we can use a slightly more complicated equation (see below on the left). You can use either one of these equations in BIO120. R 2 is equivalent to RT and R1 is equivalent to RT-10. If there is a 10°C difference the coefficient 10/(T 2-T1) becomes 1, so the equation shown on the graph is appropriate to use. For BIO120, we will be using 10°C changes as you will not have access to calculators on an exam.

If we look at the line for Q10=2 on the graph and find the rates (y-axis) at 20 °C and 30 °C, R T is the rate at the higher temperature (30) and R T-10 is the rate at 20°C. Dividing these two rates i.e., 4 / 2 = 2 which we know is the Q10 value. Now let’s consider some calculations when we don’t know all the values in the equation. 1.

For the lines representing Q10=2 and Q10=3 in the graph, add an additional point to each line for the next 10°C increase i.e., solve R T at 50°C for Q10 = 2 and RT at 40°C for Q10=3 2. Add an addition line for Q10=4. Include points at 10°C and 20°C. Assume R T-10 for the first point is 1. You can either redraw the graph or simply make changes to the graph on the right. This will be collected at the start of lecture....