Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

41.

Which of the following set of options is used in translation

  • hnRNA, tRNA, rRNA

  • mRNA, tRNA, rRNA

  • mRNA, tRNA, hnRNA

  • hnRNA, rRNA, tRNA


B.

mRNA, tRNA, rRNA

hnRNA (heterogeneous nuclear RNA) does not function until it undergoes processing. Post-transcriptional processing converts hnRNA into functional RNA, which then participates in translation (protein synthesis). mRNA, tRNA and rRNA are the functional RNAs which take part in translation.


42.

One out of the following is not responsible for biodiversity loss

  • Alien species invasion

  • Co-extinction

  • Ex-situ conservation

  • Deforestation


C.

Ex-situ conservation

Ex-situ conservation is not responsible for biodiversity loss, rather it is a method of conservation of biodiversity. It conserves selected rare plants/animals in places outside their natural homes. Alien species invasion, co-extinction and deforestation result in extinction of many species and loss of biodiversity.


43.

Which organism is used to transfer T-DNA

  • Streptomyces hygroscopicus

  • Agrobacterium tumefaciens

  • Salmonella typhi

  • Escherichia coli


B.

Agrobacterium tumefaciens

Ti plasmid (tumour inducing) from the soil bacterium Agrobacterium tumefaciens is effectively used as vector for gene transfer to plant cells. The part of Ti plasmid transferred into plant cell DNA, is called the T-DNA. This T-DNA with desired DNA spliced into it, is inserted into the chromosome of the host plant where it produces copies of itself, by migrating from one chromosomal position to another at random.


44.

Barr body is missing in the female suffering from

  • Huntington's disease

  • Tay-sach's disease

  • Klinefelter's syndrome

  • Turner's syndrome.


D.

Turner's syndrome.

In normal females, number of Barr bodies is one less than the number ofX chromosomes. One Barr body means the female has two X chromosomes. Turner's syndrome (44 + XO) is a genetic disorder that affects only females. In this condition, cells of the affected female possess only one X chromosome, instead of two. Due to the presence of only one X chromosome, no Barr body is present in females suffering from Turner's syndrome


45.

Which one ofthe following is reptilian ancestor of birds

  • Hesperornis

  • Archaeopteryx

  • Ichthyornis

  • Lycaenops


B.

Archaeopteryx

D.

Lycaenops

The first fossil birds found in the rocks of Jurassic period belonged to genera Archaeopteryx and Archaeornis. These are considered as reptilian ancestors of birds. It was about the size of a crow and possessed feathers and wings but had a long reptilian tail very much unlike the modern birds and a toothed beak. Fossils ofHesperornis, an aquatic diving bird, and Ichthyornis, a powerful flying bird, have been found from Cretaceous.


46.

Which is genetically not possible

  • Haemophilic father transfers the haemophilic gene to his son.

  • Haemophilic father transfers the haemophilic gene to his daughter.

  • Carrier mother transfers the haemophilic gene to her son.

  • Carrier mother transfers the haemophilic gene to her daughter


A.

Haemophilic father transfers the haemophilic gene to his son.

Haemophilia is a sex linked disease. It follows criss-cross inheritance in which father does not pass the sex-linked allele of a trait to his son. The same is passed to the daughter, from where it reaches the grandson, i.e., diagynic. It is because the males have only one X-chromosome which is transferred to the female offspring. Only Y-chromosome of the father is transferred to the male offspring but this sex chromosome does not carry the allele for haemophilia. Mother passes the alleles of a sex-linked trait to both sons and daughters.


47.

Select the correct explanation for the labels A, B, C and D

  • A represents the fertilised zygote.

  • B represents the stage of morula formation.

  • C represents the blastocyst.

  • D represents the blastocyst implantation


D.

D represents the blastocyst implantation

In the given figure A represents fusion of male and female gametes, B is 4 celled blastomere. C shows the morula stage, i.e., an embryo with 8 blastomeres and D is the blastocyst which gets implanted in the uterus.


48.

Primary endosperm nucleus (PEN) is formed by the fusion of

  • 2 polar nuclei + I synergid cell nucleus

  • I polar nucleus + I antipodal cell nucleus + I synergid cell nucleus

  • 2 polar nuclei+ I male gamete nucleus

  • 2 antipodal cell nuclei + I male gamete nucleus


C.

2 polar nuclei+ I male gamete nucleus

During the event of double fertilisation in angiosperms, the second male gamete fuses with the two haploid polar nuclei or diploid secondary nucleus of the central cell to form a triploid primary endosperm nucleus (PEN). This second fertilisation is called vegetative fertilisation.


49.

In rabbits, the gene for grey fur (G) is dominant over that for black fur (g). In a litter, if 50% rabbits are grey, then the possible parental cross combination is

  • GG x Gg

  • gg X gg

  • GG x GG

  • Gg x gg


D.

Gg x gg

When heterozygous grey individuals (Gg) are crossed with homozygous black individuals (gg), then grey and black individuals will be obtained in equal ratio. It is a type of test cross and can be illustrated as:


50.

Which of the following pathogens is not transmitted by a vector

  • Salmonella typhi

  • Alpha virus

  • Plasmodium

  • Wuchereria bancrofti


A.

Salmonella typhi

Salmonella typhi (causal organism of typhoid) is transmitted by faecal oral route and not by a vector. The alpha viruses are transmitted by insect vectors, most commonly by mosquitoes. Plasmodium (malarial parasite) is transmitted by female Anopheles mosquito and Wuchereria bancrofti (filarial worm) is transmitted by female Culex mosquito