No questions found
(a) Draw on Fig. 1.1 a line to show the level of water in the large test-tube. [1]
To find out how much glucose has diffused out of the Visking tubing after 15 minutes, you are provided with solutions S1, S2 and S3.
In order to find how much glucose has diffused from inside the Visking tubing into the water you will need to test a sample of the water with Benedict’s solution.
You should record the time taken for the first appearance of any green colour.
The result will be compared with the time taken for the first appearance of any green colour obtained from testing solutions S1, S2 and S3 with Benedict’s solution.
To do this you need to use the same procedure.
(b) State the volume of Benedict’s solution and the volume of the solutions (S1, S2 and S3) and the sample you are testing.
volume of Benedict’s solution .................... cm³
volume of each solution (S1, S2 or S3) .................... cm³
volume of sample .................... cm³ [1]
(c) State one variable, other than volume, which needs to be kept constant when you do the tests and describe how you will keep this variable constant.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................[2]
10. After 15 minutes, pour the water from around the Visking tubing into a beaker or container and label it sample.
11. Now test all four solutions, sample, S1, S2 and S3.
(d) (i) Prepare the space below and record your results. [4]
(ii) Estimate the concentration of glucose in the sample. [1]
..................................................................................................................................................
(iii) Suggest how you might modify this investigation to find the effect of temperature on the rate of diffusion of glucose through Visking tubing.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................[2]
(e) A student investigated the rate of diffusion of a coloured solution through agar. A Petri dish containing a layer of agar had a small well of 1 cm diameter, cut so that 10 drops of the coloured solution could be placed in the well. The distance the coloured solution diffused from the edge of the well was measured at 15 minute intervals.
Fig. 1.2 shows the surface view of the Petri dish after 75 minutes.
The results of the student’s investigation are shown in Table 1.1.
[Table_1]
(i) Plot a graph to show the results in Table 1.1. [4]
[Graph_Paper]
(ii) Use the graph to calculate the rate of diffusion of the solution between 10 minutes and 20 minutes.
Show on your graph where you took the readings. [1]
Show all the steps in your calculation. [1]
[2]
(iii) Describe and explain the trend in the rate of diffusion shown in the graph you have drawn in (e)(i).
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................[2]
(f) The ruler used to measure the distances in Table 1.1 is shown in Fig. 1.3.
State the uncertainty of the measurements using this ruler. [1]
..................................................................................................................................................
595
572
549
(a) (i) Make large, labelled drawings of two different types of cell from Fig. 2.1 and one cell from Fig. 2.2.
Indicate on the photomicrographs the cells that you have drawn. [4]
(ii) Prepare the space below so that it is suitable for you to compare and contrast the cells in Fig. 2.1 and Fig. 2.2.
Record your observations in the space which you have prepared. [5]
(iii) Calculate the actual diameter of the cell shown by the line X in Fig. 2.2.
Show all the steps in your calculation.
......................................................... µm [2]
(iv) Suggest how you would obtain a mean diameter for cells of this type.
...........................................................................................................
...........................................................................................................
........................................................................................................... [1]
(b) (i) Draw a large plan diagram of two different blood vessels shown in K1. [5]
(ii) Suggest one way in which these blood vessels are adapted for transport.
........................................................................................................... [1]
577
532
565
