Plant Kingdom Test - 28

Chrysophytes are protists which include diatoms. These are found both in fresh and marine water. Silica is deposited in the cell walls of diatoms. Silica shells of dead diatoms are nearly indestructible and thus, get accumulated at their habitat and form diatomaceous earth. Diatoms are the chief producers in the ocean.

Agar is extracted from Gracilaria and Gelidium. Agar is derived from polysaccharide; agarose, present in specific species of these algae. These algae are known as agarophytes and belong to phylum Rhodophyta. It is a red algae. The nature of agar is too gelatinous. Agar is actually the resulting mixture of two components: the linear polysaccharide; agarose, and a heterogeneous mixture of smaller molecules called as agaropectin.

A lichen is a composite organism, that emerges from algae or cyanobacteria (or both) living among filaments of a fungus in a mutually beneficial (symbiotic) relationship. The whole combined life form has properties, that are very different from properties of its component organisms.

There are many different groups of phytoplankton species found many different groups of phytoplankton species found in world’s ocean, but among the most common are diatoms, dinoflagellates. These algae have primary chloroplasts, i.e., the chloroplasts are surrounded by two membranes and probably developed through a single endosymbiotic event. Euglena is a unicellular protist which has chloroplast.The chloroplasts of red algae often have chlorophyll a and c, and phycobilins, while those of green algae have chloroplasts with chlorophyll a and b without phycobilins. thusthe correct answer is option D.

Vaucheria or Green Felt, is an alga which appears as a large, dense, dark-green, felted mass of coarse, tubular, branching filaments. It spreads over the mud in shallow ditches and on moist earth near springs or floating on the surface of ponds and in quiet fresh water. 

Ulva or sea lettuce is a species of edible green algae  which is thin flat and has a discoid holdfast. This species of Chlorophyta grows prolifically in areas which are abundant in  nutrients.  Further, this species is characterized by their sporangial and gametangial thalli being morphologically alike. Thus, the correct answer is option B.

Degrading of the cell wall gives rise to protoplasts as the cell walls are made up of a variety of polysaccharides. The cell walls can be degraded with a mixture of appropriate polysaccharide-degrading enzymes. Plant cell wall can be degraded with cellulose, pectinase and xylanase, Bacteria- lyssozyme and EDTA, Fungal cells-Chitinase. Algal cells can be degraded with chitinase, lysozyme, pectinase, sulfatase, β-glucuronidase, and laminarinase. Thus, the correct answer is option B.

In the world of filamentous freshwater algae of division Chlorophyta, the genus Zygnema, with its two stellate (star shaped) chloroplasts per cell, is a standout. Found often alongside Spirogyra, another still-water green algal genus, Zygnema species are classified as conjugate algae of phylum Gamophyta because of their means of sexual reproduction by conjugation. Forming green or yellow-brown mats of macroscopic threads or filaments, Zygnema can reproduce asexually, sexually, or vegetatively. Thus, the correct answer is option D.

Batrachospermum is one of the fresh water forms of Rhodophyceae. This alga is found in slow running shallow streams and on the banks of lakes and ponds. It is more commonly found in well aerated waters. The plants are blue-green, olive-green, violet and reddish in colour. The variation in colour is as a result, of the differences in light intensity. The species which grow in deep water are reddish or violet in colour whereas the species growing in shallow water are olive-green in colour. The alga is also known as the frog spawn or the eggs of frog, because the plants are mucilaginous, moniliform or beaded in appearance to the naked eye. The thallus is filamentous, profusely branched and with a mucilaginous feel. Hence, looks like frog eggs. The plants may reach a length of twenty centimetres and may easily be collected from well aerated water bodies. Thus, the correct answer is option A.