Test: Biological Classification 7 - From Past 28 Years Questions - NEET MCQ

African sleeping sickness disease also called trypanosomiasis common in Africa is caused by parasite Trypanosoma gambiense. The parasite is transmitted by Tse-Tse fly (Glossina palpalis).

Vector for sleeping sickness is TseTse fly (Glossina palpalis). The parasite Trypanosoma is transmitted through the bite of this fly. Tse-tse have been extensively studied because they are biological vectors of the African trypanosomiasis, deadly disease which include sleeping sickness in people and nagana in cattle. Tse-tse have existed in the modern morphological form for at least 34 million years since fossil tse-tse have been recovered from the Florissant Fossil Beds in Colorado.

Zooflagellata of Protozoan Protista. They have flagella and heterotrophic (Parasitic) mode of nutrition.

Malarial parasite, (Plasmodium vivax), Protist of class Sporozoa, digenetic  parasite causes malarial fever in human. The  malarial parasite was discovered by Laveran (1880). Sir Ronald Ross (1898) discovered that Malaria disease is spread by mosquitoes. Its life cycle completes in two organisms-Primary host, female Anopheles mosquito and man (Intermediate or Secondary host). It enters into human blood-through sporozoites. Malarial fever begins with the release of merozoites in the liver cells, from RBC of human.

Tse-Tse fly is vector of sleeping sickness disease and it transmits Trypanosoma gambiense through its bite.

Sporozoites are small, spindle-shaped, uninucleate organisms present in the salivary glands of the mosquito. Sporozoites represent the infective stage, which along with saliva inoculates into the blood stream of human and undergo schizogony.

Lichens typically grow in harsh environments in nature, most lichens, especially epiphytic fruticose species and those containing cyanobacteria, are sensitive to manufactured pollutants. Hence, they have been widely used as pollution indicator organisms.
Lichens are symbiotic associations of a fungus with a photosynthetic partner (called a photobiont or phycobiont) that can produce food for the lichen from sunlight.

Whittaker (1969) divided organisms into five kingdoms : Monera, Protista, Plantae, Fungi and Animalia. Kingdom Monera includes all prokaryotes – Mycoplasma, bacteria, actinomycetes, blue-green algae, archaebacteria, methanogens. Escherichia is bacteria, Amoeba, Gelidium come under Protista, Spirogyra is algae.

Gram +(ve) and Gram –(ve) bacteria separates on the basis of their cell wall composition. Christian Gram on the basis of staining behaviour of the cell wall with Gram’s stain, grouped bacteria into Gram +ve and Gram –ve type. The bacteria  which retain blue or purple colour after staining are Gram +ve e.g. Bacillus subtilis and which loses blue colour is Gram –ve e.g.
E. coli. In Gram  –ve stain is washed due to high lipid content in the cell wall having thick wall, Gram +ve has single layered cell wall

Paramecium has two nuclei

Trypanosoma is polymorphic i.e. it exists in different forms in the successive stages of its life cycle. These are Leishmania, Leptomonad, Crituidial and trypanosomal stages.

Amoebiasis or amoebic dysentry is caused by a parasite Entamoeba histolytica present in the upper  part of large intestine of human.
It is caused due to ingesting contaminated food or water with cyst (trophozoite) of Entamoeba. It feeds on R.B.C of intestinal blood capillaries and damages intestinal mucosa secreting an enzyme - histolysin.

Plasmodium belongs to class Sporozoa of protozoan profists. It is an endoparasite lacking any locomotony structure and contractile vacules. It reproduces through spore formation.

Azotobacter is free living soil bacteria that are able to pick up dinitrogen from the soil and fixes it into organic nitrogenous material like aminoacid. Clostridium is anaerobic free living soil N₂ fixing bacteria. Rhizobium is symbiotic N₂ fixing bacteria.

Fungi are nutritionally saprophytes, which grow on dead and decaying matter . They secrete enzyme to the external medium where digestion takes place and digested food absorbed by the body surface. They convert complex organic constituents of dead body into simple soluble forms. That is why Fungi are decomposers.

Laveran discovered Plasmodium in R.B.C of human beings and concluded that malaria is caused by Plasmodium vivax. Sir Ronal Ross (1896) was the first to observe oocytes of Plamodium in female Anopheles.

In human beings different types of malaria are caused by 4 different species of Plasmodium. They are :
1. Benign Tertian Malaria –  Plasmodium vivax.
2. Malignant (Pernicious or cerebral) Tertian Malaria – Plasmodium falciparum.
3. Quartan Malaria – Plasmodium malariae.
4. Mild Tertian Malaria –  Plasmodium ovale.

Chemosynthetic bacteria does not require sunlight as a source of energy directly or indirectly. The energy for the synthesis of food is obtained by the oxidation of certain inorganic substances present in the medium. The chemical energy obtained from oxidation reaction is trapped in ATP molecules. The ATP is used in CO₂ assimilation.

I. African sleeping sickness disease also called as trypansomiasis common in western and central parts of African continent.
II. The disease is caused by parasite Trypanosoma gambiense of class zooflagellata.
III. The parasite is transmitted (vector) through bite of Tse-Tse fly (Glossina palpalis).
IV. The disease appears when the causal organism enters into cerebrospinal fluid of human.
V. Trypanosoma is an obligate parasite, Digenetic and Polymorphic organism.

Contractile vacuole in Amoeba and Paramecium maintain the water balance of the cell. This is known as osmoregulation.

In bacteria asexual reproduction through binary fission is the most common method of multiplication. Sexual reproduction which comprises of syngamy and meiosis is entirely absent. Hence no gamete formation takes place. In sexually reproducing organism alternation of generation occurs.

P. vivax is a causative agent of malaria. The life cycle of Plasmodium is characterized by an exogenous sexual phase (sporogony), in which multiplication occurs in female Anopheles mosquitos and an endogenous asexual phase (schizogony) which take place in the RBCs of the infected host.

Lichens are composite organisms representing a symbiotic association between fungus and a algae. It can be Crustose, Foliose and Fruticose types. They are the pioneer organisms in a new habitat. Lichens used as indicator of air pollution. It does grow in the environment where pollution level is high, SO₂ is strong air pollutant and lichens are very sensitive to SO₂.

Escherichia coli, lives as a symbiont in human intestine. 

The bacterial genome/nucleoid is made of single circular double stranded DNA without histone protein as it is a prokaryotic organisms. The genome contains some 100 chemical sites or loci. Each locus contains many genes. E coli contains about 4000 genes.