Multiple Choice Questions

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Given below is a representation of a kind of chromosomal mutation. What is the kind of mutation represented

  • Deletion

  • Duplication

  • Inversion

  • Reciprocal translocation


C.

Inversion

During inversion a segment of chromosome gets inverted in the process of reattachment. Thus a chromosome having the genes A B C D E F G H I in linear order may get the segment DEF inverted. The new arrangement will be A B C F E D G H I. It is a chromosome aberration entailing two breaks in a chromosome followed by a reversal of the segment and consequently ofthe gene sequence in the segment. Pericentric inversion includes the centromere in the inverted segment, whereas paracentric inversions do not.


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Assertion : In humans, the gamete contributed by the male determines whether the child produced will be male or female.

Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on X chromosome and some on Y-chromosome.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


When two mutations are located in the same functional unit or in different functional units, then it is confirmed by :

  • test cross

  • back cross

  • reciprocal cross

  • complementation test


Lack of independent assortment of genes A and B in fruit fly Drosophila is due to :

  • repulsion

  • linkage

  • crossing-over

  • recombination


How many different types of gametes can be formed by F1 progeny, resulting from the following cross

AA BB CC x aa bb cc

  • 3

  • 8

  • 27

  • 64


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Given below is a pedigree chart of a family with five children. It shows the inheritance of attached ear-lobes as opposed to the free ones. The squares represent the male individuals and circles the female individuals. Which one of the following conclusions drawn is correct

  • The parents are homozygous recessive.

  • The trait is Y-linked.

  • The parents are homozygous dominant.

  • The parents are heterozygous.


Which of the following is dominant character according to Mendel ?

  • Dwarf plant and yellow fruit

  • Terminal fruit and wrinkled seed

  • White testa and yellow pericarp

  • Green coloured fruit and rounded seed


One of the genes present exclusively on the X-chromosome in humans is concerned with

  • baldness

  • red-green colour blindness

  • facial hair/moustaches in males

  • night blindness


Mirabilis jalapa is an example of

  • complete dominance

  • supplementary gene

  • incomplete dominance

  • complementary gene


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A baby has been born with a small tail. It is a case exhibiting

  • retrogressive evolution

  • mutation

  • atavism

  • metamorphosis


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