Skip to main content
A-LevelBiologyTransport in plantsMay/June 2020Paper 3 Q218 Marks

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]

✓ Correct Answer

The correct answer is . This question tests the candidate's understanding of transport in plants within the Biologysyllabus. The examiner's mark scheme requires...

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🔒

Unlock the Examiner's Answer

Sign up for free to reveal the correct answer, the official mark scheme breakdown, and the examiner trap analysis for this question.

Sign Up Free to Unlock →

Join thousands of Cambridge students already using Oracle Prep

About This A-Level Biology Question

This structured question appeared in the Cambridge A-Level Biology (9700) May/June 2020 examination, Paper 3 Variant 2. It tests the topic of Transport in plants and is worth 18 marks.

Oracle Prep provides AI-powered practice for all Cambridge O-Level and A-Level subjects. Our platform includes topic predictions with 87.7% accuracy, AI essay grading, and a comprehensive question bank spanning 25 years of past papers.

© 2026 Oracle Prep — The AI-Powered Cambridge Exam Engine