Skip to content
← Theoretical 1

Q30 - Light Colour Effects on Photosynthesis in Arabidopsis

Theoretical 1 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Light Reactions & Photophosphorylation

Arabidopsis thaliana was used in a study on photosynthesis. A. thaliana plants of same age, with leaf blades of equal shape and size, were placed under various light sources that emitted different colours. Three plants were exposed to each light source. The groupings of were as follows: Group a: blue light, Group b: green light, Group c: red light, Group d: blue and red, Group e: yellow and green. After 5 days of illumination at equal intensity comparable to normal day light, in terms of total amount of photons and duration, the plant’s physiological parameters were compared. The compensation point was measured using sunlight.

Using the information and data, determine which of the statements are true or which are false.

A. The plants of group "a" showed the highest photosynthesis rate.
B. Among the various groups, the light compensation point for CO2 fixation was the lowest for group "b".
C. The biomass of group "d" plants was higher than group "c" plants.
D. At light intensities just above the compensation point, the rate of photosynthesis of group "e" is expected to increase linearly with light.
← Previous: Q29 Next: Q31 →

Question reproduced from IBO 2018, Theoretical Paper 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)