31 Years NEET Previous Year Questions: Biological Classification - 2 -

Mad cow disease is actually Bovine Spongiform Encephalopathy or BSE. In this disease cattles in Britain got their brain become spongy & ultimately gradual degradation of nervous system. It is caused by some virus like but nucleic acid devoid proteinaceous particles called prions (proteinaceous infectious particle).

While working at the Rockefeller Institute, Brown reported isolation of a PPLO from human arthritic joint tissue in 1938. In 1949, Diennes reported to the 7th International Rheumatology Congress the isolation of PPLO from the genitourinary tracts of men afflicted with arthritis. In discussing the significance of this observation, Brown reported successful treatment of arthritic patients in 1949 with a new antibiotic called aureomycin (Clark, 1997).

A domain of prokaryotic organisms containing the archaebacteria including the methanogens, which produce methane; the thermoacidophilic bacteria, which live in extremely hot and acidic environments, & the halophilic bacteria, which can only function at high salt concentrations are abundant in the world’s oceans. 

Phylogenetic system of classification is based on evolutionary relationships. This phylogenetic classification system names only clades-groups of organisms that are all descended from a common ancestor. Under a system of phylogenetic classification, we could name any clade on this tree. For example, the Testudines, Squamata, Archosauria, and Crocodylomorpha all form clades.

Single celled eukaryotes are included in protista. Protista includes all unicellular and colonial eukaryotes except green and red algae. It is also known as kingdom of unicellular eukaryotes.

Membrane bound organelles are absent in Streptococcus. Streptococcus is a bacterium that is included under kingdom Monera. Monerans are prokaryotes which lack membrane bound organelles like mitochondria, E.R, Golgi etc.
Saccharomyces, Chlamydomonas and Plasmodium are eukaryotes that have membrane bound organelles.

Virus envelope is known as capsid. The capsid is composed of protein subunits called capsomere.

Eubacteria are  prokaryotic but eubacteria are enclosed by plasma membrane like eukaryotic cells.

The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the heterotrophic bacteria. Lactobacillis bacteria convert milk into curd.

Cyanobacteria are also referred as blue green algae, they perform oxygenic photosynthesis. They are most successful autotrophic organisms on earth which one found in all types of environment - fresh water, sea water, salt marshes, moist rocks, tree trunks, moist soils, hot springs, frozen waters.

Kingdom Protista has brought together Chlamydomonas, Chlorella (earlier placed in Algae within Plants and both having cell walls) with Paramoecium and Amoeba (which were earlier placed in the animal kingdom which lack cell wall).

Archaebactera live in some of the most harsh habitats such as extreme salty areas (halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens) and in deep sea water.

Fungi lack chlorophyll, hence, they do not prepare their food by photosynthesis. They can grow where organic material is available. So, they are heterotrophs that acquire their nutrient by absorption and store in the form of glycogen.

Heterocysts are large sized, thick-walled specialised cells which occur in terminal, intercalary or lateral position in filamentous cyanobacteria, e.g., Nostoc. They have enzyme nitrogenase and specialised to perform    biological    nitrogen    fixation.