Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

51.

Which of the following conditions represents a case of codominant genes

  • A gene expresses itself, suppressing the phenotypic effect of its alleles.

  • Genes that are similar in phenotypic effect when present separately, but when together interact to produce a different trait.

  • Alleles, both of which interact to produce a trait, which may or may not resemble either of the parental types.

  • Alleles, each of which produces an independent effect in a heterozygous condition.


D.

Alleles, each of which produces an independent effect in a heterozygous condition.

Codominance is the phenomenon when the two alleles of a gene neither show dominant recessive relationship nor show intermediate condition, but both of them express themselves independently in heterozygous condition. This has been reported in roan coat colour of cattle (i.e., patches of2 different colours on the skin).


52.

Assertion: The honeybee queen copulates only once in her life time.

Reason: The honeybee queen can lay fertilised as well as unfertilised eggs.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion.

Queen is the only fertile female in beehive, having immensely developed ovaries. She lives for several successive years laying about 2000 or more eggs a day. The queen has a remarkable capacity of controlling the fertilisation of its eggs. A fertilised egg is laid in a worker or queen cell, while an unfertilised egg in a drone cell, the latter develops parthenogenetically. The queen mates only once in her life time. The sperms stored in her spermatheca fertilise her eggs as long as she lives.


53.

Refer to the given figure and choose the organism not related to the condition shown here.

  • Microsporum

  • Trichophyton

  • W. malayi

  • Epidermophyton


B.

Trichophyton

The person shown in the given figure is suffering from ringworm infection. Many fungi belonging to the genera Microsporum, Trichophyton and Epidermophyton are responsible for ringworm disease. Appearance of dry, scaly lesions on skin, nails and scalp are the main symptoms of this disease.


54.

Assertion: Flavr-Savr tomato was the first transgenic commercial crop that entered the market.

Reason: Roundup variety of soybean was prepared through breeding.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


C.

If assertion is true but reason is false.

The Flavr-Savr tomato, was the first genetically modified fruit/vegetable to reach the market in USA. Roundup ready soybean is a genetically modified herbicide tolerant cultivar.


55.

Assertion: Somatic hybridisation is a process where protoplasts of two desired plants can be fused to develop improved plants.

Reason: Cross breeding can also induce variability

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion.

Cross Breeding is the process of causing animals to mate with another species, or of causing plants to reproduce with another species.


56.

Assertion: XX-XY type of sex determination mechanism is an example of female heterogamety and is found in Drosophila.

Reason: Male heterogamety is seen in moths where males produce two different types of gamete.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


D.

If both assertion and reason are false.

Chromosomal determination of sex is based on heterogamety or occurrence of two types of gamete in one of the two sexes. In Drosophila XX-XY type of sex determination is found where males are heterogametic. In moths, ZO-ZZ type of sex determination occur where males are homogametic.


57.

Assertion: Analogous organs are a result of divergent evolution.

Reason: Eye of octopus and of mammals depict divergent evolution.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


D.

If both assertion and reason are false.

The organs which have similar functions but are different in their structural details and origin are called analogous organs. The analogous structures are the result of convergent evolution. Eyes of octopus and of mammals show different patterns of structure. Yet they perform similar functions, so they depict convergent evolution.


58.

Assertion: Restriction enzymes cut the strand of DNA to produce sticky ends.

Reason: Stickiness of the ends facilitates the action of the enzyme DNA polymerase.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


C.

If assertion is true but reason is false.

Restriction enzyme, a type of endonuclease, functions by "inspecting" the length of a DNA sequence. Once it finds a recognition sequence, it binds and cuts each of the two strands of the double helix at specific point leaving single stranded portions at the ends. This results in overhanging stretches called sticky ends. These are named so because they form hydrogen bonds with their complementary counter parts, i.e. they can join similar complementary end of DNA fragment from some other source with the help of DNA ligase. This stickiness of the ends facilitates the action of the enzyme DNA ligase, not DNA polymerase.


59.

Assertion: Neurospora is commonly called water mould.

Reason: It belongs to basidiomycetes fungi.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


D.

If both assertion and reason are false.

Neurospora is commonly called pink/red bread mould or pink mould. It belongs to Class Ascomycetes (sac fungi). It is used in experimental genetics as it can be grown easily in a definite medium in a laboratory.


60.

Assertion: Chimpanzee is the closest relative of the present day humans.

Reason: The banding pattern in some autosomes of man and chimpanzee is remarkably similar.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


A.

If both assertion and reason are true and reason is the correct explanation of assertion.

I has been observed that the banding pattern of some human chromosomes is very similar to the banding pattern of the corresponding chromosomes in apes. It shows common origin of man and chimpanzee and their close relatedness.