Multiple Choice Questions

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Assertion: Persons suffering from haemophilia fail to produce blood clotting factor VIII.

Reason: Prothrombin producing platelets in such persons are found in very low concentration.

  • 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

Haemophilia, also called bleeder's disease is a X-linked recessive disorder. The person which contains the recessive gene for haemophilia lacks a normal clotting substance (thromboplastin) in blood. So minor injuries cause continuous bleeding and ultimate death of the person due to hemorrhages.

Haemophilia is of two types : type A characterized by lack of antihaemophilic globulin (factor VIII) and type B characterized by a defect in plasma thromboplastic component (factor IX).
Prothrombin is an inactive plasma protein and is produced by liver. It helps in blood clotting. It is not produced by platelets.


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Assertion : Haemophilia is a recessive sex linked disease.

Reason : Haemophilia occurs due to mutation of a structural gene on chromosome 15.

  • 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


Assertion: A geneticist crossed two plants, he got 50% tall and 50% dwarf progenies.

Reason: It follows Mendelian law as one of the parent plant might be heterozygous.

  • 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.


Assertion: Blood group 'O' have anti-A & antiB antibodies.

Reason: It does not have any antigens.

  • 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.


XO-chromosomal abnormality in human beings causes

  • Turner's syndrome

  • Down's syndrome

  • Klinefelter's syndrome

  • None of these


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Pure line breed refers to

  • heterozygosity only

  • heterozygosity and linkage

  • homozygosity only

  • homozygosity and self assortment


Gene which suppresses other gene's activity but does not lie on the same locus is called as

  • epistatic

  • supplementary

  • hypostatic

  • codominant


The distance between two genes in a chromosome is measured in cross-over units which represent

  • ratio of crossing over between them

  • percentage of crossing over between them

  • number of crossing over between them

  • none of these.


Assertion : A gamete may carry either of the traits but not both.

Reason : This is Mendel's second law or law of independent assortment.

  • 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


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If a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, the offsprings will be

  • half- white flowered

  • half- red flowered

  • all white flowered

  • all red flowered


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