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Aim: To investigate the ideal conditions for enzyme action

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Aim: To investigate the ideal conditions for enzyme action A Brief description of how enzymes work: Enzymes have one specific job and one specific substrate. The lock and key theory suggests that there is only one key per lock and this is a good way of explaining about enzymes. Here is an example: Each enzyme has a certain place where they will produce a product. Examples of digestive enzymes are: * The protease enzyme (pepsin) acts on proteins and produces amino acids - Acid in the stomach is needed. * The amylase enzyme acts on carbohydrates and produces sugars. * The carbohydrase enzyme acts on starch and produces glucose. * The lipase enzyme acts on fats also known as lipids and produces fatty acids and glycerol - bile is needed, bile breaks up fat and neutralises the stomach to slightly acidic. Factors that could effect the experiment: Temperature: Temperature will effect my experiment in two ways, if it is too hot the enzymes will be denatured. Denatured means the bonds in the enzyme break and the enzyme loses its shape and it can no longer do its specific job. ...read more.


Absorption: The small intestine consists of duodenum and ileum. Nearly all the absorption happens in the ileum. The ileum is quite long so has a large absorption area. The blood absorbs the nutrients from the food here. Method: We will use temperature as our independent value, the one we will change. We will keep the pH the same throughout. We will time each one so the time will be different for each. We are choosing pepsin (protease enzyme) as our enzyme, to find out the ideal conditions for enzyme action. We will be digesting egg white (also called albumen) and when it goes clear we will know it has been digested. We will set up different test tubes with pepsin, albumen and hydrochloric acid in (this is used because acid is present in the stomach.) The tubes will be heated with a water bath to different temperatures from 0 - 60 degrees Celsius. We will keep the amount of acid, egg white and pepsin the same; we will have 3cm cubed of pepsin, 5cm cubed of egg white and 1cm cubed of hydrochloric acid. ...read more.


Our temperature range is 50 degrees Celsius. Planning our results: When we have completed our experiment I will place the results in a table, similar to the one below. I will also show my results in a graph comparing the temperature with the time. Though I will only be able to plot the ones which finish dissolving. Some may not complete the process. On the graph the x-axis will be showing the time in minutes and the y axis will be showing the temperature in degrees Celsius. I will check my prediction and explain the reasons, and why I was correct or incorrect. Doing this will increase my knowledge and understanding. Preliminary work: Our preliminary work consists of finding out that acid is needed in the stomach for digestion to work, and if relevant bile is needed to digest using lipase enzymes. The information found about acid being needed was essential to this experiment as we needed to add Hydrochloric acid to make it work. We also drew a graph in the past that showed us the effects of temperature and pH also on the protease enzyme; this showed no particular pattern so I was interested in the part that temperature against time played in the process. ...read more.

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