Oxygen is not produced during photosynthesis by
- Cycas
- Green sulphur bacteria
- Chara
- Nostoc
Answer
(2) Green sulphur bacteria
Solution
As per NCERT, van Niel's studies on purple and green bacteria showed that these bacteria use H2S (not H2O) as the hydrogen donor.
⇒ Their photosynthesis is anoxygenic: sulphur, not oxygen, is the by-product.
2H2S + CO2 light [CH2O] + H2O + 2S
Cycas (gymnosperm), Chara (green alga) and Nostoc (cyanobacterium) use water as the hydrogen donor and release O2.
Answer: (2)