Multiple Choice Questions

Advertisement

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


C.

If assertion is true but reason is false

The law of segregation states that the two alleles controlling each character maintain identity in the organism but during the formation of gametes or spores by meiosis move apart due to separation of the homologous chromosomes which bear them, so that each gamete or spore receives only one allele of each character on random basis.

Since the gametes or spores possess one allele of each character, they are always pure. The law of segregation is, therefore, also called the law of purity of gametes/spores.

Mendel's second law or the law of independent assortment states that the alleles of different characters located in different pairs of homologous chromosomes are independent of one another in their segregation during gamete formation and in coming together into the offspring by fertilization, both processes occurring randomly.


Advertisement

Pure line breed refers to

  • heterozygosity only

  • heterozygosity and linkage

  • homozygosity only

  • homozygosity and self assortment


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.


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.


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

  • epistatic

  • supplementary

  • hypostatic

  • codominant


Advertisement

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.


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


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


XO-chromosomal abnormality in human beings causes

  • Turner's syndrome

  • Down's syndrome

  • Klinefelter's syndrome

  • None of these


Advertisement
<

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.


Advertisement