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Question 18N.2.HL.TZ0.4e.ii

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Date November 2018 Marks available [Maximum mark: 2] Reference code 18N.2.HL.TZ0.4e.ii
Level HL Paper 2 Time zone TZ0
Command term Describe Question number e.ii Adapted from N/A
e.ii.
[Maximum mark: 2]
18N.2.HL.TZ0.4e.ii

Boreal forests stretch across Canada, Russia and Scandinavia. This northern ecosystem accounts for 29 % of the world’s forest areas. The long, cold winters favour tall evergreen trees with either needles or scale-like leaves. These trees are wind-pollinated and their seeds are not enclosed in a fruit. The photograph shows a typical boreal forest in winter.

(e.ii)

In some boreal species, Rubisco is down-regulated during the winter months. Describe the role of Rubisco in photosynthesis.

[2]

Markscheme

a. carbon fixation/fixes carbon dioxide/carboxylation
OR
rubisco is used in the Calvin cycle/light independent stage ✔

b. carbon dioxide linked to RuBP/ribulose bisphosphate «by rubisco» ✔

c. glycerate 3-phosphate/glycerate phosphate produced «by rubisco» ✔

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