Question

Which of the following can be used as a bacteriological filter
A ) Gelidium
B) Batrachospermum
C) Oscillatoria
D) Cosmarium

Answer 1

Hint:Bacteriological filters are used to bacteria as these filters have porous membranes that are used to trap bacteria. Artificial bacterial filers are also used such as glass filters having pores and ceramic filters made up of kaolin. Membrane filters are most commonly used for bacteria.

Complete answer: Option D) is correct Cosmarium belongs to green algae and is a desmid. It belongs to the division Charophyta. The cell membrane of cosmarium is highly porous which can filter small organisms such as bacteria. Hence it is used as a bacteriological filter. Two semi cells of Cosmarium are joined by the isthmus where the nucleus is present. It moves by mucilage propulsion as mucilage absorbs water and swells which propels the cell to move forward. The cell wall has pores and pits.
Option a) is incorrect Gelidium is used for the preparation of agar which is a polysaccharide used in the food and cosmetic production Gelidium belongs to red algae. Gelidium can be grown on low nutrient conditions and in eulittoral and sublittoral zones.
Option b) is incorrect Batrachospermum belongs to red algae and is not used as a bacteriological filter It ranges from violet to blue-green color. Long, branched, and filamentous body. It forms the major biomass of the algal community. It shows the alternation of generation between haploid free-living gametophyte and carposporophyte.
Option c) is incorrect Oscillatoria is a filamentous cyanobacterium. It is most commonly found in freshwater environments and performs photosynthesis. Long filaments break into fragments known as hormogonia which grow into a new organism.

Note: Cosmarium is a green alga that is used as a bacteriological filter because of the highly porous membrane. Gelidium is used for the preparation of agar polysaccharides. Batrachospermum is red algae with a filamentous body, Oscillators are also filamentous and reproduce by the formation of hormogonia.