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Question 19N.3.HL.TZ0.2c

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Date November 2019 Marks available [Maximum mark: 2] Reference code 19N.3.HL.TZ0.2c
Level HL Paper 3 Time zone TZ0
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 2]
19N.3.HL.TZ0.2c

A student designed an experiment to study the transpiration through the leaves of a tomato plant (Solanum lycopersicum). Measurements were taken in the initial conditions with five leaves on a tomato shoot and then again after each of the five leaves was removed.

[Source: R. C. Hodson and J. Acuff . 2006. Water transport in plants: anatomy and physiology in
Tested Studies for Laboratory Teaching, Volume 27 pp 163–183]

(c)

Explain how the results in the graph could have been obtained.

[2]

Markscheme

a. using a potometer ✔ Accept transpirometer but not respirometer.

b. leafy shoot attached to a reservoir and a graduated «capillary» tube ✔

c. as transpiration increases water uptake «by roots» also increases ✔

d. distance/time for bubble «in capillary tube» to travel is used to measure transpiration rate ✔