Water moves through xylem vessel elements in plants. The diameter of xylem vessel elements varies between different species of plant. You will measure how quickly coloured water moves through xylem vessel elements of different diameters. You will use microscope slides to represent xylem vessel elements of different diameters. You are provided with the materials shown in Table 2.1. Table 2.1 labelled description hazard P container with 6 pieces of paper none R beaker containing coloured water none Carry out step 1 to step 9. 1. Put one clean, dry microscope slide on the bench. 2. Put two pieces of paper from the container labelled P on top of the microscope slide. 3. Put another microscope slide on top of the paper. 4. Put tape around the two microscope slides to hold them together as shown in [Figure 2.1A]. 5. Label this pair of microscope slides, A. 6. Repeat step 1 to step 4 using four pieces of paper instead of two pieces of paper, as shown in [Figure 2.1B]. 7. Label this pair of microscope slides, B. 8. Hold A by the side edges and remove the paper. You should be left with a gap as shown in [Figure 2.2]. 9. Repeat step 8 for B. 10. Put A into the beaker labelled R, as shown in [Figure 2.3]. Start timing immediately and record in Table 2.2 the time it takes for the coloured water to reach the top of the pair of microscope slides. If the time taken is longer than 60 seconds record the result as 'more than 60'. 11. Repeat step 10 using B instead of A. Fig. 2.4 is a photomicrograph of a stained transverse section through a leaf. You are not expected to be familiar with this specimen. [Figure 2.4] Use a sharp pencil for drawing. You are expected to draw the correct shape and proportions of the different tissues. Fig. 2.5 is a photomicrograph of a stained transverse section through a leaf of a different type of plant. You are not expected to be familiar with this specimen. [Figure 2.5] Fig. 2.6 is the same photomicrograph as in Fig. 2.5 but with line Z added to show the diameter of the vascular bundle. [Figure 2.6]

1. (a)(i)Record your results in Table 2.2. Table 2.2 pair of microscope slides number of pieces of paper used to make gap time for coloured water to reach the top of the microscope slides/s A 2 B 4[1]
2. (a)(ii)Identify one significant source of error when measuring the dependent variable.[1]
3. (a)(iii)Using your results in Table 2.2 suggest how the diameter of xylem vessels affects the transport of water in a plant.[1]
4. (b)(i)Draw a large plan diagram of the section shown in [Figure 2.4]. Use one ruled label line and label to identify the upper epidermis.[6]
5. (b)(ii)Identify the observable differences between the leaf in [Figure 2.4] and the leaf in [Figure 2.5]. Record the observable differences in Table 2.3. Table 2.3 feature Fig. 2.4 Fig 2.5[4]
6. (c)(i)Use the magnification and the line Z on [Figure 2.6] to calculate the actual diameter of the vascular bundle. Show all the steps in your working and use appropriate units. actual diameter of vascular bundle =[4]
7. (c)(ii)State one piece of apparatus you would use to measure a specimen on a slide using a microscope fitted with an eyepiece graticule.[1]

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