Question

A filamentous green alga characterized by cap cells is
A. Spirogyra
B. Oedogonium
C. Ulothrix
D.Zygnema

Answer 1

Algae is a division of the kingdom Plantae. Algae are photosynthetic, green-colored, thalloid, and oxygenic plants. The bodies of algae are highly variable in shape and it varies from unicellular to filamentous to colonial forms.

Complete answer:
Spirogyra –
Spirogyra is a member of the Chlorophyceae class of algae. Chlorophyceae consists of green algae. Spirogyra has an unbranched and filamentous body. It has ribbon-shaped chloroplasts.
Oedogonium –
Oedogonium is a member of the Chlorophyceae class of algae. Chlorophyceae consists of green algae. Oedogonium has an unbranched and filamentous body. It has a reticulated or ribbon-shaped chloroplast. It has easily identifiable distinctive rings present at the apical ends of certain cells that are known as the cap cells. Moreover, each cellular division creates a new ring on the cap cells.
Ulothrix –
Ulothrix is a member of the Chlorophyceae class of algae. Chlorophyceae consists of green algae. Ulothrix has an unbranched and filamentous body. It has collar-shaped or girdle-shaped chloroplasts.
Zygnema –
Zygnema is a member of the Chlorophyceae class of algae. Chlorophyceae consists of green algae. Zygnema has a filamentous body. It has star-shaped chloroplasts.
Thus, based on the above information we can conclude that a filamentous green alga characterized by cap cells is Oedogonium.

Hence, the correct answer is an option (B).

Note: Oedogonium reproduces by the process of the formation of zoospores. Zoospores are always formed during favorable conditions. The zoospores attach themselves with the substratum through the head to form the new plants. They are extremely important as they fix the heavy metals in freshwater ecosystems.