Back to your test review
Start free test
A scientist cultured Cladophora in a suspension of Azotobacter and illuminated the culture with light split by a prism. The bacteria accumulated mainly in the region of
Your answer:
Correct answer: (b)
Advertisement
Explanation
Why (b) is correct
This is Engelmann's experiment. He split light with a prism and placed Cladophora in a suspension of aerobic bacteria (here Azotobacter). The bacteria gathered where the alga gave off the most oxygen, which was in the blue and red light. These are the wavelengths that chlorophyll absorbs most strongly for photosynthesis.
Why the other options are wrong
- (a) · your answer Green light is mostly reflected by chlorophyll, so little photosynthesis and little oxygen come from the green region.
- (c) · your answer Green light is poorly absorbed; the bacteria did not crowd there.
- (d) · your answer Orange and yellow light are absorbed only weakly by chlorophyll, so oxygen release there is low.
NCERT point: Engelmann's action spectrum resembles roughly the absorption spectra of chlorophyll a and b, with peaks in the blue and red regions.
Thank you! We will check this question.
Practise Photosynthesis in Higher Plants
Take a free 15-question NEET Biology test on this chapter. Timed, scored instantly.