If random errors are unavoidable due to equipment limitations, then the best way to minimise them is to repeat the experiment as many times as possible to average out the error.
ENZYMEX CALCULATOR SERIAL
For example, an adjustable pipette will be much better at measuring out a few millilitres of a solution when performing a serial dilution than using a 50 mL beaker. However, selecting the correct tools for the correct job can help minimise random errors. For example, if your balance is only accurate to a value of 0.1 grams but you need to measure out 250 milligrams of a substance. Random errors are most likely to occur because of the limitations of the equipment that you are using. Similarly it is vital to properly clean and dry cuvettes, fill them using a pipette, handle them only using gloves, and if possible, store them in a cuvette rack. An example of a systematic error would be if you were using a cuvette that was stained or scratched, so less light pass would through your sample and all readings using that cuvette would be affected. Systematic errors arise from either imperfections in the equipment being used, or by improper technique in the laboratory. How do we measure the reaction rates of enzymes?Įrrors can happen in even the best experiments, but attention to detail and good experimental design can help to minimise both random and systematic errors.
What kinds of enzymes do researchers investigate? The independent variable (the variable we are manipulating, for example, enzyme concentration) could be represented by plotting multiple lines on the same graph. The spectrophotometer shown below is similar to a colorimeter, although it measures the transmission, rather than the absorbtion of light.Īs the dependent variable (the variable being tested) is the rate of reaction, we need to ensure that the measurements that we are taking are plotted against time. The reaction rate can therefore be measured with a colorimeter, which will indicate the absorbance of light through the product. Alternatively, the extracellular enzyme tripsin breaks down casein in milk, changing its colour from white to clear. In this reaction the produced oxygen gas can be collected and used as a way of measuring the reaction rate. For example, catalase is a common intracellular enzyme that speeds the decomposition of hydrogen peroxide (a byproduct of metabolism) into water and oxygen. Given the range of enzyme controlled reactions, there is no single best method for measuring reaction rates as the products of reactions vary greatly. This structure is represented in the lock and key and induced-fit models of enzyme action, with the induced-fit model including the changes that can occur in enzyme shape to allow catalysis. Any changes to this three dimensional structure can change the shape of the active site and cause the enzyme to become denatured. Enzymes are made from long chains of amino acids, folded precisely into a three dimensional shape (or tertiary structure) with an active site that allows it to operate as a catalyst. You will be aware that enzymes are biological catalysts, meaning they increase the rate of chemical reactions without undergoing any permanent change. How do you measure the rate of enzyme controlled reactions?Įnzymes operate throughout biological organisms, both intracellularly and extracellularly. The more we understand about how enzymes function and the reactions they control, the better we can use the machinery of nature to benefit human endeavours. Living cells and organisms could not function without enzyme controlled reactions. What can affect enzyme controlled reactions?
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