Investigating the Effects of Temperature on the Rate of Respiration of Blowfly Larvae

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Investigating the Effects of Temperature on the Rate of Respiration of Blowfly Larvae

This experiment was setup to investigate the effects of temperature on the rate of respiration of blowfly larvae.

Background Knowledge

The maggots involved in this investigation were blowflies at the larval stage of development, and they breathe through spiracles in the anterior and posterior segments. The respiratory tracts are not as developed at this stage, as the organism is not capable of flight, and so it respires less oxygen than an adult blowfly. They feed on dead organic matter. The respiration of an organism involves an intricate use of enzymes, and so some knowledge about them is necessary.
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However, recent studies point towards the induced-fit hypothesis, which means that the substrate and the enzyme are not identical, yet in the presence of the substrate the active site changes slightly, in order to make it a more "snug" fit. These theories pertain to a further point - the fact that an enzyme is specific; the majority just have one possible type of substrate molecule. An increase in temperature affects the rate of an enzyme-controlled reaction in two ways. First of all, the kinetic energy of all of the molecules is increased, thus increasing their speed. If they move faster, they have more chance of an enzyme colliding with a substrate molecule, and so reacting. This is known as collision theory. The increase of rate can be determined by the Q10 law. This states that for every 10 degrees in temperature in an enzyme-controlled reaction, the rate of that reaction will double, until 40 degrees is reached. After this point, the enzyme may start to denature. This is when a certain factor affects the bonds holding the amino acids together, and they start to break, eventually resulting in the enzyme unravelling. Generally this occurs between 40 and 60 degrees.

Equipment List

* Respirometer (already assembled)

* Blowfly larvae

* Balance

* Soda lime

* cotton wool

* 250ml