Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

61.

Name one frequently used fungicide

  • griseofulvin

  • chloramphenicol

  • cycocel

  • ethylene


A.

griseofulvin

Fungicides are the chemicals, which kill fungal pathogen. Griseofulvin produced by Penicillium griseofulvum is toxic to several phytopathogenic fungi, such as those causing powdery mildew, rusts, botrytis and others.

Chloramphenicol is an antibiotic that works by stopping the growth of bacteria. It is used to treat bacterial eye infections.

Cycocel is the most widely used plant growth regulators for ornamentals, including bedding plants and herbaceous crops.

Ethylene is an ageing hormone. It helps the developmental processes such as ripening, senescence and abscission. It also regulates many aspects of growth and development of the plant.


62.

The father of green revolution in India is

  • Calvin

  • Haberlandt

  • Norman Borlaug

  • Swaminathan


D.

Swaminathan

MS Swaminathan is known as the Father of Green Revolution. It was the rapid increase in agricultural production during 1960- 1970s. 


63.

Which of the following is not a Green-house gas?

  • N2O

  • CFC

  • O3

  • CO2


C.

O3

The gases responsible for Green-house effect are CO2, CH4, CFCs and N2O. The Green-house gases cause global warming. The CO2 is considered as most dominant factor responsible for Green- house effect.


64.

The vector of the kala-azar is

  • Aedes sp

  • Anopheles stephenis

  • Culex fatigans

  • Phlebotomus sp


D.

Phlebotomus sp

Leishmaniasis or kala- azar is a disease caused by the parasites of Leishmania type. It is mainly caused by Leishmania donovani. The parasite spreads by sandfly (Phebotomus) bite.


65.

Which of the following be named for DNA produced from RNA?

  • A- DNA

  • B- DNA

  • C- DNA

  • Z- DNA


C.

C- DNA

The DNA synthesized on template of RNA by the enzyme reverse transcriptase is called complementary DNA (C-DNA).

A-DNA is a right-handed double helix fairly similar to the more common B-DNA form, but with a shorter, more compact helical structure whose base pairs are not perpendicular to the helix-axis as in B-DNA.

 In B-DNA, the most common double helical structure found in nature, the double helix is right-handed with about 10–10.5 base pairs per turn. The double helix structure of DNA contains a major groove and minor groove.

Z- DNA is the double helix that has a left- handed rather than the usual right handed twist and the suagr- phosphate backbone followsa zig-zag course.


66.

Freon gas causing stratospheric O3 depletion is mainly released from

  • refrigerator

  • automobile

  • thermal power plant

  • steel industry


A.

refrigerator

Major sources of chlorofluorocarbons or CFCs are leaking air conditioners, refrigeration units, evaporation of industrial solvents, production of plastic foams and propellants in aerosol spray cans.


67.

Increase of BOD in water leads to

  • increase in the dissolved O2 concentration

  • decrease in the dissolved O2 concentration

  • maintenance of dissolved O2 concentration at the same level

  • no effect on dissolved O2 concentration


B.

decrease in the dissolved O2 concentration

Biochemical Oxygen Demand (BOD) is the oxygen in milligrams required-for five days in one litre of water at 20°C for the micro-organisms to metabolise organic waste. Increase of BOD in water leads to decrease in the dissolved oxygen concentration.


68.

Pests which only feed and oviposit on crop are called

  • major pests

  • minor pests

  • accidental pests

  • occasional pests


A.

major pests

The pests are the communities of life that are capable of causing damage to cultivated crops, fruits, vegetables, wood and forest wealth.


69.

India became a party to 'Convention on biglogical diversity' in the year

  • 1994

  • 1993

  • 1992

  • 1988


A.

1994

Earth summit at Rio de Janeiro (1992) Brazil, promoted convention on Biological Diversity. India became a party to this convention on Biological Diversity in May; 1994.


70.

In which stage of its life cycle, the silk moth begins to produce silk fibre?

  • 3rd instar larva

  • 4th instar larva

  • 5th instar larva

  • Pupa


D.

Pupa

The caterpillar larva hatches from egg of silkmoth. The full grown caterpillar larva grows into pupa. Its salivary glands now secrete a sticky fluid through a narrow pore of its spinning apparatus called spinneret situated on hypopharynx. The sticky substance turns into the fine long and solid thread of silk.