Question

Which one shows isogamy with non-flagellated gametes?
A. Spirogyra
B. Ulothrix
C. Ectocarpus
D. Sargassum

Answer 1

Hint: A filamentous green algae having a characteristic feature that involves the presence of the spirally arranged chloroplasts that help then in the process of photosynthesis making them autotrophs.

Complete answer:
The isogamy with non-flagellated gametes is found in Spirogyra. Spirogyra is commonly known as water silk. They reproduce by both means sexual as well as sexual. During sexual reproduction, the tap non-flagellated gametes come together which are different in structure.

Additional Information: -The gametes which are non-motile and do not have flagella for movement and locomotion are called non-flagellates.
-The gametes produced in algae are of three types: isogametes (both the gametes are motile and of equal size), anisogametes (both the gametes are motile but are of different size), and oogamy (male gamete is small and motile fixed with large and non-motile female gamete).
-The flagella are the hair-like structure present on the outer surface of the gametes which helps in the movement.
-Spirogyra is found in freshwater having clear eutrophic water.
-They grow underwater but when the sunlight is enough a large amount of oxygen is produced forming bubbles in between their filaments.
-They appear to be slimy green colored filaments on the surface of the water bodies.
-The Spirogyra consists of a cell wall, a nucleus, a paranoid, and chloroplasts which are normally arranged.
So, the correct answer is ‘Spirogyra’.

Note: Ulothrix belongs to the green algae but the filaments are unbranched. They are generally found in low temperatures and fresh as well as marine water habitat and reproduce vegetatively. Ectocarpus belongs to the brown algae which are filamentous found mostly in the cold waters with a small body. Sargassum is a small seaweed which belongs to the brown algae. They are generally free-floating and found in deep and shallow waters.