Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

71.

SO2 pollution is indicated by

  • Desmodium (grasses)

  • Sphagnum (mosses)

  • Usnea (lichens)

  • Cucurbita (climbers)


C.

Usnea (lichens)

Lichens are widely used as environmental indicators or bio-indicators. Lichens are injured by sulphur dioxide (SO2). Lichens have also shown sensitivity to some other pollutants, such as heavy metals and Other Gaseous Toxics in Air , but for the most part lichen damage can be attributed to SO2.


72.

Which one of the following ancestors of man first time showed bipedal movement

  • Australopithecus

  • Cro-magnon

  • Java ape man

  • Peking mann


A.

Australopithecus

Australopithecus was the first ape man having fully bipedal locomotion. Its thighs and hips were adapted for erect standing, walking and running. This man lived from 4 to 1.5 million years ago in caves during Pleistocene period.


73.

Out of A-T, G-C pairing, bases of DNA may exist in alternate valency state owing to arrangement called

  • tautomerisational mutation

  • analogue substitution

  • point mutation

  • frameshift mutation


A.

tautomerisational mutation

In the early 1950s, guanine and thymine were generally portrayed in the enol form, although there was little data to support the predominance of one form over the other. James Watson and Francis Crick discovered that by using the keto forms instead of the enol forms, they could "form" two base pairs, an adenine thymine pair and a guanine-cytosine pair, that had the same overall size and shape. These base pairs formed the basis for Watson and Crick's model of DNA.

The process of changing keto form in to enol form of a given organic compound is known as tautomerisational mutation.


74.

The life span of honey bee drone is

  • 3-4 months

  • 1-2 months

  • 6-7 months

  • 10-12 months


B.

1-2 months

Drones are the male honey bees, developed parthenogenetically and have a life span of about 5 weeks (or 1-2 months), while life span of a worker bee is about 16 weeks (or 3-4 months)


75.

The chemical nature of chromatin is as follows

  • nucleic acids

  • nucleic acid and histone proteins

  • nucleic acids, histone and non-histone proteins

  • nucleic acids and non-histone proteins


C.

nucleic acids, histone and non-histone proteins

Chromatin is the material, of which eukaryotic chromosomes are composed. Chemically, chromatin consists of nucleic acids, histone and non-histone proteins.


76.

Scirpophage incertulus is an example of

  • monophagus pest

  • diphagus pest

  • oligophagus pest

  • polyphagus pest


A.

monophagus pest

Scirpophaga incertelus is a monophagus pest that feeds on a single plant.


77.

During replication of DNA, Okazaki fragments are formed in the direction of

  • 3' ➔ 5'

  • 5' ➔ 3'

  • 5'➔5'

  • 3' ➔ 3'


B.

5' ➔ 3'


78.

Molecular scissors, which cut DNA at specific site is

  • pectinase

  • polymerase

  • restriction endonuclease

  • ligase


C.

restriction endonuclease

 A restriction enzyme or restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within the molecule known as restriction sites. 


79.

Trophic levels in ecosystem is formed by

  • only bacteria

  • only plants

  • only herbivores

  • organisms linked in food chain


D.

organisms linked in food chain

Trophic levels are the divisions or levels of food chain characterized by specific method of obtaining food (and energy).


80.

Sporopollenin is chemically

  • homopolysaccharide

  • fatty substance

  • protein

  • heteropolysaccharide


B.

fatty substance

Sporopollenin is biologically most resistant organic material (fatty substance) found in the exine (outer wall) of spores and pollen grains. It consists of complex polymers with an emperical formula (C92H142O36) formed by oxidative polymerization of carotenoids and their esters.