Multiple Choice Questions

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In which one of the following sets of three items each belong to the category mentioned against them

  • Lysine, glycine, thiamine - amino acids

  • Myosin, oxytocin and gastrin - hormones

  • Rennin, helicase and hyaluronidase - enzymes

  • Optic nerve, oculomotor, vagus - sensory nerves


C.

Rennin, helicase and hyaluronidase - enzymes

Rennin, helicase and hyaluronicasc are all enzymes.

Rennin (chymosin), secreted by the stomach is responsible for clotting milk. It acts on a soluble milk protein (caseinogen) to converts it into the insoluble form casein.

Helicase unwinds double stranded helical DNA during replication.

Hyaluronidase is able to digest hyaluronic acid (major glycosaminoglycan) and is therefore important in modulating the removal of cell matrix in order to facilitate cell movement or tissue organization.

Thiamine is not an amino acid, it is vitamin B1, which is active in the form of thiamin pyrophosphate, a coenzyme in decarboxylation reactions in carbohydrate metabolism. A deficiency of vitamin B1 leads to beriberi.

Myosin is a contractile protein found in eukaryotic tissue. interacts with actin to bring about contraction of muscle or cell movement. Among optic, oculomotor and vagus, which are cranial nerves, optic is sensory in nature, oculomotor is motor and vagus is mixed sensory nerves.


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Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration is called

  • reciprocal cross

  • dihybrid crossn

  • test cross

  • back cross


Assertion: Polytene chromosomes have a high amount of DNA.

Reason: Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.

  • 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.


Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in F2 generation what proportion of the progeny is likely to resemble either parent?

  • None

  • Less than 5 percent

  • One third

  • Half


Given below is a highly simplified representation of the human sex chromosomes from a karyotype

  • The gene a and b could be of

    colour blindness and body height

  • attached ear lobe and Rhesus blood group

  • haemophilia and red-green colour blindness

  • phenylketonuria and haemophilia


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Genes present in the cytoplasm of eukaryotic cells are found in

  • mitochondria and inherited via egg cytoplasm

  • lysosomes and peroxisomes

  • Golgi bodies and smooth endoplasmic reticulum

  • plastids and inherited via male gamete


Primary source of allelic variation is

  • independent assortment

  • recombination

  • mutation

  • polyploidy


The "cri-du-chat" syndrome is caused by change in chromosome structure involving

  • deletion

  • duplication

  • inversion

  • translocation


Given below is a pedigree chart showing the inheritance ofa certain sex-linked trait in humans

The trait traced in the above pedigree chart is

  • dominant X- linked

  • recessive X- linked

  • dominant Y- linked

  • recessive Y- linked


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Which one of the following pairs of features is a good example of polygenic inheritance

  • Human height and skin colour

  • ABO blood group in humans and flower colour of Mirabilis jalapa

  • Hair pigment of mouse and tongue rolling in humans

  • Human eye colour and sickle cell anaemia


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