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Date November 2018 Marks available 2 Reference code 18N.3.HL.TZ0.2
Level Higher level Paper Paper 3 Time zone TZ0 / no time zone
Command term Describe Question number 2 Adapted from N/A

Question

The micrograph shows a section through the root of a dicotyledonous plant (× 400).

Label tissues X and Y.

[2]
a.

Calculate the actual width along line A-B of the parenchyma cell shown.

[1]
b.

Describe the distribution of vascular tissues in the stem of dicotyledonous plants.

[2]
c.

Markscheme

a. X: phloem ✔

b. Y: xylem ✔

a.

A-B = 7 mm 400

OR

17.5 μm ✔

 

Accept answers in the range of 17 to 19 μm

b.

a. stem vascular tissue is in bundles ✔

b. «bundles» form a ring

c. phloem is towards outside «of bundle»
OR
xylem is towards centre «of bundle» ✔

 

Allow answers in an annotated drawing

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Additional higher level » Topic 9: Plant biology » 9.1 Transport in the xylem of plants
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Additional higher level » Topic 9: Plant biology » 9.2 Transport in the phloem of plants
Additional higher level » Topic 9: Plant biology
Additional higher level

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