A gene showing codominance has

(1) one allele dominant on the other

(2) alleles tightly linked on the same chromosome

(3) alleles that are recessive to each other

(4) both alleles independently expressed in the heterozygote

In his classic experiments on pea plants, Mendel did not use

(1) seed colour

(2) pod length

(3) seed shape

(4) flower position

How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments?

(1) Five

(2) Six

(3) Eight

(4) Seven

Which one from those given below is the period of Mendel's hybridisation experiments?

(1) 1856 - 1863

(2) 1840 - 1850

(3) 1857 - 1869

(4) 1870 - 1877

Among the following characters, which one was not considered by Mendel in his experiments on pea?

(1) Stem - Tall or Dwarf

(2) Trichomes - Glandular or Non-glandular

(3) Seed - Green or Yellow

(4) Pod - Inflated or Constricted

Thalassemia and sickle-cell anaemia are caused due to a problem in globin molecule synthesis. Select the correct statement.

(1) Both are due to a qualitative defect in globin chain synthesis

(2) Both are due to a quantitative defect globin chain synthesis

(3) Thalassemia is due to less synthesis of globin molecules

(4) Sickle-cells anaemia is due to a quantitative problem of globin molecules

A disease caused by an autosomal primary non-disjunction is 

(1) Down's syndrone

(2) Kilnerfelter's syndrome

(3) Turner's syndrome

(4) Sickle-cell anemia

The mechanism that causes a gene to move from one linkage group to another is called 

(1) inversion

(2) duplication

(3) translocation

(4) crossing-over

A true breeding plant is

(1) one that is able to breed on its own

(2) produced due to cross-pollination among unrelated plants

(3) near homozugous and produces offspring of its own kind

(4) always homozygous recessive in its genetic constitution

If a colourblind man marries a woman who is homozygous for normal colour vision, the probalility of their son being colourblind is 

(1) 0

(2) 0.5

(3) 0.75

(4) 1