Question

pH Effects on Enzyme Activity Another environmental factor regulates enzyme activity is pH (the level of acidity or alkalinity of a solution). As you may recall, the pH scale extends from 0 (very acidic) to 7 (neutral) to 14 (very alkaline or basic). We can use chemicals called buffers to help maintain a specific pH in solution. The pH scale and buffers are described in your online text (section 2.2, https://openstax.org/books/concepts- biology/pages/2-2-water). The spot plate diagram below shows a series of IKI tests on each of the four samples measured at different times. Based on this diagram, click to select the number of minutes needed to digest essentially all the starch in the sample. If a sample never becomes negative for starch, select 'more than 14'. (You need to be within two minutes to receive full credit.) Table 7-4: IKI Test for the Effect of pH on Amylase Activity (modified from lab manual) Tube Stareh 4 ml of Buffer Enzyme Minutes until the IKI test for "C" Solution (ml) at pH S olution (m ) starch becomes negative 15 pll 40 pH 6.0 pH 8.0 pH 100 Tube 1 Imagine that the amylase enzymes used in this experiment were isolated from a fungus. The fungus secretes amylase into the environment around its cells and absorbs any maltose that is released. Where is it most likely that this fungus grows naturally: a peat bog at pH 4, a swamp at pH 7, or an industrial waste pit at pH 10? (Assume all three environments have the same amount of starch available.) 0000 Environment:

Answer 1

* IKI test on each of the four samples measured at different times. so Tubel - Starch gets negative in the sample - at 3 minutes (PH 4.0) 22 - Starch gets negative in the sample at @ 5-6 minutes. (PH. 6.0) VOLT Totally clear at 6 minutes. - Starch gets totally cleared off at around 10 minutes. (PH. 8) Starts to disappear from & minutes onwards. Tubey - Starch doesn't get clear wo it talies" more than 14 minutes 4 CH 10) non lo ne not at 6 minutee on The enzyme seems to best work around pH 4. Colowe yellow shows absence Colour blue - shows presence of starch of starch. Tube # Starch som (ul) pH in (4m) Buffer og pH 4.0 ovo in " M e ning negative. c. G - pH 6.0 Enzyme Minutes until the solution IKI test for (ML) Starch becomes h = eng minutes." 6 minutes 1 11 minutes solr.& -more than 14 cox à minutes. G pH & od o pH lo