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

(1) reciprocal cross

(2) test cross

(3) dihybrid cross

(4) back cross

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

The gene a and b could be of

(1) colour blindness and body height

(2) attached ear lobe and Rhesus blood group

(3) haemophilia and red-green colour blindness

(4) phenylketonuria and haemophilia

In which one of the following combinations (a-d) of the number of chromosomes is the present day hexaploid wheat correctly represented?

XO-chromosomal abnormality in human beings causes

(1) Turner's syndrome

(2) Down's syndrome

(3) Kilnefelter's syndrome

(4) none of these.

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

(1) epistatic

(2) supplemetary

(3) hypostatic

(4) codominant

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

(1) ratio of crossing over between them

(2) percentage of crossing over between them

(3) number of crossing over between them

(4) none of these

How many genome types are present in a typical green plants cell?

(1) More than Five

(2) More than Ten

(3) Two

(4) Three

Percentage of recombination between A and B is 9%, A and C is 17%, B and C is 26%, then the arrangement of genes is 

(1) ABC

(2) ACB

(3) BCA

(4) BAC

Which of the following conditions represents a case of co-dominance genes?

(1) A gene expresses itself, suppressing the phenotypic effect of its alleles. 

(2) Genes that are similar in phenotypic effect when present separately, but when together interact to produce a different trait.

(3) Alleles, both of which interact to produce a  trait, which may or may not resemble either of the parental types.

(4) Alleles, each of which produces an independent effect in a heterozygous condition. 

Which of the following disorders are caused due to recessive autosomal mutations?

(1) Turner's syndrome and sickle cell anaemia

(2) Edward's syndrome and Down's syndrome

(3) Cystic fibrosis and phenylketonuria

(4) Alzheimer's disease and Huntington's chorea