The Effect Of Enzyme Concentration On Enzyme Activity
The pancreatic duct in individuals who have cystic fibrosis frequently becomes blocked, reducing or preventing the release of pancreatic enzymes into the small intestine. The aim of this activity is to investigate the effect of a reduction in enzyme concentration on the rate of reaction, in this case the breakdown of protein by protease enzymes.
Aim – Milk powder contains a white protein called casein. A white suspension of milk powder clears on the addition of the enzyme trypsin. The aim of this experiment is to investigate the effect of enzyme concentration on enzyme activity. We will observe how fast the milk turns transparent by changing the concentration of the enzyme on milk.
Hypothesis – The higher the concentration of enzymes, the faster the protein will be broken down, and therefore the egg white will turn transparent faster.
Appropriate observations have to be made to validly test a hypothesis or idea. The term “observations” is taken to include measurements. Validity is the measure of confidence that can be placed in a conclusion. After deciding upon a dependant variable to vary within the experiment, the method of measurement should also be known, the measurement taken should be valid e.g. the volume of oxygen collected in 30 seconds is a valid measurement of rate of catalase activity.
Valid results are derived through precise, repeatable measurements and observations, made with apparatus and experimental procedures that are suitable for the task.
Ideally a large number of replicates (repeat measurements) should be taken, and any results that vary considerably from the others should be repeated or discounted. A mean can be calculated to be
representative of the set of results. The pressure of time usually puts a limit on the number of replicates that can be taken.
To be reliable, measurements should also be accurate. To be accurate a measurement should be close to the true value. Precision involves the choice of apparatus and the skill with which it is used.
I had to also be aware of the different types of error that could occur in my experiment, systematic, random, and human errors. To overcome systematic problems I will need to know how to use apparatus correctly, to avoid human error I will have to give my full attention and concentration towards the experiment. To avoid random errors, I have to control changes in the material used or the conditions in which they are carried out in, as this will all affect the final result we produce.
If we follow this we should be able to produce valid results.
To carry out this experiment, the following apparatus are needed:
· Standard alkali trypsin solution
· Milk powder
· Standard laboratory glassware and apparatus
· Stop clock
Safety – An important aspect of good practical work is safety. To work safely during practical work, I made sure I followed each of the following rules.
1. Do not bring non-essential materials into the lab. Keep bags and coats outside of the lab as it could get in the way, and cause injury.
2. No food or drink is allowed in the lab at any time. We will be working with some fairly nasty chemicals and some exercises involve bacteria. It can be dangerous if the chemicals r ingested.
3. The eyes are particularly sensitive to chemicals, and provide a good portal of entry for microorganisms; the best way to avoid contact is to keep your hands away from your face as much as possible and to wear safety goggles at all times. Gloves may also have to be worn when handling hazardous chemicals.
4. We will be working with stains in some exercises that will not wash out of cloth, and so lab coats are needed.
5. Keep long hair tied back and ties tucked in, as we will have open flames in some exercises.
6. Dispose of waste material...
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