Question

Plant like photosynthesis that releases O₂ occurs in

(A) cyanobacteria.

(B) archaea.

(C) gram-positive bacteria.

(D) chemoautotrophic bacteria.

Short answer

(A) The option “cyanobacteria” is correct.

(B) The option “archaea” is incorrect.

(C) The option “gram-positive bacteria” is incorrect.

(D) The option chemoautotrophic bacteria” is incorrect.

Step-by-step solution

Step:1: Photosynthesis

Photosynthesis is the process by which plants generate energy by processing light energy. It takes place only in plants, not in animals. This process requires carbon dioxide and sunlight as reactants and produces glucose and oxygen as products.

Step: 2: Explanation of option (A)

Cyanobacteria are bacteria that belong to kingdom Protista. They obtain energy through the process of photosynthesis. They use sunlight as an energy source and release oxygen into the atmosphere.

Thus, photosynthesis occurs in cyanobacteria, and they release oxygen.

Therefore, this option is correct.

Explanation of option (B)

Archaea contain different types of bacteria, such as halophiles and methanogens. They cannot perform photosynthesis to obtain energy. They depend on other substances for energy.

Thus, they cannot release oxygen, as they don’t perform photosynthesis.

Therefore, this option is incorrect.

Explanation of option (C)

Bacteria are classified into two types that are gram-positive and gram-negative; they cannot prepare their food themselves like plants. They depend on other substances such as plants and animals for their growth and survival.

Thus, they cannot perform photosynthesis and do not release oxygen into the atmosphere.

Therefore, this option is incorrect.

Explanation of option (D)

Chemoautotrophic bacteria such as methanogenic bacteria and sulfur-oxidizing bacteria use inorganic resources as energy resources such as ammonia and hydrogen sulfide. They do not perform photosynthesis.

Thus, they cannot release oxygen into the environment.

Therefore, this option is incorrect.