9. Gas exchange
A section of Biology, 9700
Listing 10 of 240 questions
is a photomicrograph showing a transverse section through a bronchus and the surrounding lung tissue. P Q P R magnification x40 Q Calculate the actual diameter of the lumen of the bronchus using the line P–Q. Write down the formula used to make your calculation. Show your working and give your answer to the nearest micrometre (µm). formula actual diameter = µm In , the area labelled R shows a section through some alveoli. Name the tissue that lines the air spaces of the alveoli. Suggest how the alveoli are adapted for gas exchange. In the leaves of plants, both gas exchange and transpiration occur through open stomata. Suggest how the arrangement of cells in the leaf of a dicotyledonous plant contributes to the loss of water by transpiration. shows the mean transpiration rate of a xerophyte between 08:00 and 19:00. 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 mean transpiration rate / arbitrary units time of day Describe the data shown in . Suggest why the transpiration rate changed between 09:00 and 10:00.
9700_s19_qp_23
THEORY
2019
Paper 2, Variant 3
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Questions Discovered
240