Question

Which one of the following categories of organisms do not evolve oxygen during photosynthesis ?

• A. Red algae
• B. Photosynthetic bacteria
• C. $C_4$ plants with Kranz anatomy
• D. Blue green algae

Answer 1

Answer: (B)

Red algae, $C_4$ plants arid blue green algae use light energy for reducing $C{O}_2$ to organic compounds and water $\left(H_{2}O\right)$ as a source of electrons. Hence, oxygen $\left(O_2\right)$ is evolved but in case of photosyiithetic bacteria, light energy is used for $C{O}_2$ reduction but water is never used as source of electrons, hence, $O_2$ is never evolved during bacterial photosynthesis.