[填空题]
In an investigation into the effect of solnxgdqyi8s)a.x92zv, :*qh nap0 r n n*ute concentration on diffusiobj: w8zvd*c g8n rate, starch solutions, of varying concentrat: dv8g zj8cw*bions, were placed inside starch permeable membrane balloons. Each balloon was put into a beaker of distilled water and at 3 minute intervals, samples were taken from the solution surrounding the membrane balloons in each beaker, placed on spotting tiles and tested for the presence of starch. The time taken for a positive test to show was recorded for each trial.
The results are shown in the graph.
1.1.Identify the dependent and independent variable in this investigation.
1.2.State one variable, other than time of testing, that should be kept constant in this investigation to ensure the results are valid.
2.Describe a positive test for starch.
3.Explain why the method used in this study would not be appropriate for an investigation into the effects of solute concentration on active transport.
4.1.Samples taken from the 5% and 10% starch solution both tested positive for starch after 3 minutes. Suggest a way in which the experiment could be improved to provide a more accurate result.
The accuracy of the experiment could be improved by the frequency.
4.2.Predict the time taken for a positive starch test for a starch concentration of 3%.
A positive test for starch, at 3%, would take approximately minutes.
5.Suggest modifications to the methodology that would make it suitable to investigate the effect of glucose concentration on the rate of diffusion.
