BIO 102 | Study Mode

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Question 51
A
observable characteristics of existing organisms
B
the ancestral lineage of existing organisms
C
dendogram based on DNA characteristics
D
sexual characteristics.
Explanation
Phenetic classification is a type of numerical taxonomy. In this type of classification the organisms are arranged according to overall similarity of existing organisms based on available characters.

It is also called adansonian taxonomy because the same was first attempted by Adanson (1763), of course on the basis of external traits only. Numerical taxonomy evolved around 1950.

It has received impetus with the availability of calculating machines and computers. In numerical taxonomy as many characters as possible are employed for evaluating degree of similarity and difference. All characteristics used in analysis are given equal weightage and importance.

A proper selection of characters, their organisation and analysis in the light of current knowledge is key to success of this method. A lot of subjectivity can creep in depending upon the judgement of the biosystematist. No weightage is given to the quantity of the character present.


Correct option: A
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Question 52
A
lysozymes
B
lipolytic
C
lytic
D
lysogenic.
Explanation
Viruses like bacteriophage T4 undergo lytic cycle that involves lysis of bacteria. The replication cycle of bacteriophage T4 consists of following phases

(i) Adsorption of the phage to bacterial or host cell. Then the viral genetic material penetrates into the host cell.

(ii) Eclipse period involves the synthesis of new phage DNA and proteins.

(iii) Maturation involves the assembly of phage DNA into the protein coat.

(iv) Lysis of host cell occurs and releases infective progeny phases.


Correct option: C
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Question 53
A
DNA is not present at any stage in the life cycle of retroviruses
B
Retroviruses carry gene for RNA-dependent DNA polymerase
C
The genetic material in mature retroviruses is RNA
D
Retroviruses are causative agents for certain kinds of cancer in man.
Explanation
Retroviruses contain RNA as genetic material and this RNA is converted to DNA using enzyme reverse transcriptase.

Correct option: A
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Question 54
A
they provide a beautiful area for recreation
B
one can observe tropical plants there
C
they allow ex-situ conservation of germ plasm
D
they provide the natural habitat for wild life.
Explanation
Ex situ conservation means offsite conservation. It is the process of protecting endangered species of plants and animals by removing it from an unsafe or threatened habitat and placing it or part of it under the care of humans. Botanical gardens serve as ex situ conservation of germplasm of different plants, to maintain rare and endemic plant species and also to provide recreation and knowledge about plants to a comnian man.

Correct option: C
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Question 55
A
International Code of Botanical Nomenclature
B
International Congress of Biological Names
C
Indian Code of Botanical Nomenclature
D
Indian Congress of Biological Names.
Explanation
The International Code of Botanical Nomenclature (ICBN) is a set of rules and recommendations dealing with the formal botanical names given to plant. The foundations of ICBN are given in book written by C. Linnaeus named Philosophia Botanica. It is independent of zoological nomenclature, ilie rank of species is basic and relative orders of the ranks of taxa are as: species, genus, tribe, family, order, series, class, division and kingdom.

The different ranks or categories have following specific endings of their names as division phyla, class, and family-aceae.


Correct option: A
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Question 56
A
Physarum
B
Thiobacillus
C
Anabaena
D
Rhizopus.
Explanation
Slime moulds are peculiar protista that normally take the form of amoebae, but under certain conditions develop fruiting bodies that release spores, superficially similar to the sporangia of fungi.

The order physarales include Physarum species. The fruiting bodies (sporangia) are characterized by the presence of abundant amount of calcium salt. The order comprises 142 species which are placed under 12 genera. Physarum polycephalam is the best known. The somatic phase is multinucleate, diploid holocarpic Plasmodium which is the product of syngamy.


Correct option: A
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Question 57
A
excess NO2 and SO2 from burning fossil fuels
B
excess production of NH3 by industry and coal gas
C
excess release of carbon monoxide by incomplete combustion
D
excess formation of CO2 by combustion and animal respiration. (1988, 89)
Explanation
Acid rain refers to the precipitation with a pH of less than 5. It is a mixture of H2SO4 and HNO3, the ratio of the two acids vary depending on the relative quantities of sulphur oxides and nitrogen oxides present in the atmosphere. These oxides are mainly produced by combustion of fossil fuels, smelters, industries, power plants, automobile exhausts etc.

Correct option: A
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Question 58
A
hydrocarbon
B
carbon dioxide
C
carbon monoxide
D
sulphur dioxide.
Explanation
The common gaseous pollutants are oxides of carbon (CO and CO2), oxides of nitrogen (NO and NO2) oxides of sulphur (SO2 and SO3), all these together contribute 90% of the global air pollution. Out of all these CO2 is not a pollutant normally, the green plants, by photosynthesis balance the CO2 and O2 ratios in the air to a great extent, whereas others like carbon monoxide, NO2 etc are poisonous gases.

Correct option: B
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Question 59
A
plankton
B
nekton
C
plankton and nekton
D
benthos.
Explanation
Planktons are passively floating in upper water, nektons are actively swimming while benthos lead sedentary life upon the sea bottom. Planktons are producers and are present in large number.

Correct option: A
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Question 60
A
closely related organism growing in different niches
B
closely related organisms growing in the same area/niche
C
distantly related organisms growing in the same habitat
D
distantly related organisms growing in different niches. (1988)
Explanation
Competition is rivalry for obtaining the same resource. Competition of light, nutrients and space is most severe between closely related organisms growing in the same area/niche, due to overproduction of population in the same area/niche.

Correct option: B

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