Pepsin and Protein Essay -- Papers

Pepsin and Protein Question Is the rate at which Pepsin digests protein affected by temperature? Prediction I predict that it is affected by temperature. The optimum temperature will be between 30 °C and 40 °C. This is because the average human body temperature is 37 °C. At 0-20 °C (which includes the groups 0-10 and 10-20) the pepsin will not digest the protein for a long time. This is because it is a too cold environment for the enzyme to work most effectively and quickly. At 20-30 °C the pepsin will work slightly more quickly than at 0-20, but not as well as at 30-40, because it is reaching the optimum temperature, though it is not quite there yet. At the higher temperatures (i.e. 40-70 °C) the enzymes will not work as well. You may think that, using the pattern up to 30-40 °C, the higher the temperature, the quicker pepsin works. But this is not the case because when it gets too hot, the enzymes start to lose their shape. Enzymes use a very precise "lock and key" method to digest food. For example pepsin, which is a protease enzyme, has a shape exclusive for digesting protein molecules, and as soon as it changes its shape (in this case due to heat) it cannot digest the molecule it was originally designed to digest. Once it has changed shape it cannot change back again. The "lock and key" is demonstrated below with diagrams. The pepsin molecule locks onto the Glucose molecules are very glucose molecule and breaks it complex but they still need down into smaller particles. specially designed enzymes that fit the molecules perfectly to break them down. If the temperature is too high and the enzyme changes ... ...ironment pepsin works quickest in. (see prediction). The independent variable will be the temperature range - 0-70 °C in jumps of 10 °C.This is what to change for the investigation. Nothing else must change, because then it would be an unfair test. The dependant variable will be the rate at which pepsin digests the egg white suspension - in other words how long the mixture takes to go clear. This will give you the results. For a fair test the controlled variables will be the amount of egg white suspension (25cm ²), the amount of pepsin (5cm ²) and the amount of hydrochloric acid (5 drops from the pipette) used. Also how often the mixture is checked will be a controlled variable. To make the results as accurate and reliable as possible, each temperature range will be repeated 5 times, and an average will be taken.