Monday, 16 January 2012

2.9 Effect of temperature on the rate of reaction

Understand how the functioning of enzymes can be affected by changes in temperature

There are two main principles for this topic:

  1. If we increase the temperature, then we increase the 'average' kinetic energy with the particles.
  2. If we increase the kinetic energy, then we increase the number of collisions, so therefore we will have more reactions
The particles here, in particular, are the substrates (s) and the enzyme (e)
Enzyme + Substrate => Enzyme Substrate Complex + Enzyme 
Here we are looking at temperature affects it:

At low temperatures, we will except a slower rate of reaction, but as we increase the temperature, the effect is that the kinetic energy of both e and s increase so more complexes are formed more quickly.
However, we find that we reach a temperature at which the rate of reaction decreases quite dramatically

In section A, we a increasing the average kinetic energy of both reactants e and s, so we have more collisions and more reactions. After a given temperature (section C), the rate of reaction declines really quickly, this is because the kinetic energy is changing the shape of the active site of the enzyme - so it doesn't work to produce products. This is called denatured (not killed). The peak of the curve is at a given temperature so that the maximum rate is achieved at the temperature which is called the optimum temperature.

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