1. You have performed the experiment (your practical 3, Metabolism experiment).
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Question
1. You have performed the experiment (your practical 3, Metabolism experiment). You wish to tell your friend about this experiment so they can replicate it exactly. Write a methods section for this practical. This methods section should be brief. Do not write lists of materials and do not write in bullet-points or numbered form- write full sentences. You must describe how the activity of amylase was calculated in the germinating barley (section 2g). Describe the steps involved using words, not calculations. The methods should also explain (i) why a boiled control was used in 2f, and (ii) how to correct the value of amylase activity for any of the stages if an achromic point had been reached for the control experiment. Recommended word length 250-350 words). 2. Your friend has performed the experiment and collected the data below. From this data, calculate the amylase activity of the germinating barley (3-day old seedlings), showing all steps of your working. (No part of this answer counts towards to word limit) Weight Volume Time to achromic point NA 0 Da 0.458 8.5ml 3 Da 1.378 8.4ml 12.43 minutes 7 Da 1.897 8.6ml 17.25 minutes 3. The following information relates to part A and B of this question. One of the aims of this experiment was to 'interpret results in terms of the metabolic role of amylase during plant A) How well do you think this experiment fulfilled this aim? Explain your reasoning, including at least one strength and one weakness in the experiment in terms of addressing this aim. Consider the weakness you identified in your answer above: B) How would you improve/modify the experiment to address this weakness, so that the collected results better reflect the stated experimental aim? Recommended word length 550-650 words, split between A and B as you see fit).Explanation / Answer
1) Amylase hydrolyses starch at alpha 1,4 glycosidic linkage to produce glucose and maltose. The amylase activity can be measured in germinating barley seeds in the following way. First around ten barley seeds were taken and patted dry and their weight is measured. Then, using a mortor and pestle, they are crushed to powder.
Then, 10 ml of buffer solution is added and again they are crushed. After filtering the extract, they are added into a measuring cylinder. A five fold dilution is made after taking 5 ml of the solution and mixing it up with 20 ml of the buffer solution. A control solution is made by mixing 5 ml of the solution in a water bath for 10 minutes and cooling it.
To determine the activity of amylase per mass of germinating tissues, a drop of iodine is added in 21 wells. Reaction mixture was then prepared by adding 5 ml of buffer and 1 ml of 0.5% starch solution in a test tube. One drop of reaction mixture was added to iodine which turns blue black.
Then, starting with well 0 on the ceramic plate, one drop of amylase reaction mixture was added to the iodine. At one minute interval, another drop of the amylase reaction mixture was added to another well. This was repeated until the achromic point was reached. When the achromic point had been reached, the time elapsed was recorded. At achromic point, the amount of maltose is detected using Benedict's reagent.
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