Fig. 1 shows a seedling placed under a lamp that shines from one side. After two days, the shoot bends towards the lamp. The leaves receive more light on th...
Question 1 Report
Fig. 1 shows a seedling placed under a lamp that shines from one side. After two days, the shoot bends towards the lamp. The leaves receive more light on the side facing the lamp. In another part of the investigation, one seedling is rotated slowly on a turntable so that all sides receive similar light exposure. The students measure shoot height and leaf area at the end of one week. They relate the response to the need for leaves to absorb light for photosynthesis.
(a) Identify the name of the response shown by the bending shoot. [1]
(b) Explain how bending towards light can increase the rate of photosynthesis. [2]
(c) Use the investigation to state why the turntable is used. [2]
(d) Give one product of photosynthesis that can be used in respiration by plant cells. [1]
Answer Details
(a) Positive phototropism [1] (b) More leaf surface faces the light [1]; more light is absorbed by chlorophyll, increasing photosynthesis [1] (c) It exposes all sides of the plant to similar light [1]; so direction of light is controlled / bending due to one-sided light is prevented [1] (d) Glucose [1]
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