when a tall pea-plant was selfed, it produced one-fourth of its progeny as dwarf.  Explain with the help of a cross.

2

(a)

A Corss between a red flower-bearing plant and a white flower-bearing plant of antirrhinum produced all plants having pin flowers.  Work out a cross to explain how this is possible.

2

(a)

With the help of a Punnett square, find the percentage of homozygous tall plants in a F₂ population involving a true-breeding tall and a true-breeding dwarf pea plant.

2

(a)

In a dihybrid cross, while-eyed, yellow-bodied female Drosophila crossed with red-eyed, brown-bodied male Drosphila produced in F₂ generation, 1.3 per cent recombinats and 98.7 per cent progeny with parental type combinations.  This observation of Morgan deviated from Mendelian F₂ phenotypic dihybrid ratio.  Explain giving reasons Morgan's observations.

2

(a)

Differentiate between Dominance and Recessive.

2

(a)

How are alleles of a particular gene different from each other? Explain its significance.

2

(a)

Give the Mendelian monohybrid ratio.  How is it mathematically condensable to the binomial expression?

2

(a)

In dogs, black coat colour is dominant over white.  What coloured dog will you choose to breed with a given back dog, in order to find its genotype.  What is this type of cross known as?

2

(a)

Thalassemia \(\alpha\) is different from thalassemia \(\beta\).  Justify.

2

(a)

What will be the consequence, if cytokinesis does not follow the telophase stage of cell division?  What term is given to this phenomenon?

2

(a)

Mendel published his work on inheritance of characters in 1865, but it remained unrecognized till 1900.Give three reasons for the delay in accepting his work.

2

(a)

How many genes are responsible for?
(i) ABO system of blood group
(ii) Skin colour in human.

2

(a)

Linkage and crossing over of genes are alternatives of each other justify.

2

(a)

What are the kinds of mutation according to phenotypic effect?

2

(a)

A man with blood group A and his wife blood group B have a son with blood group O, father claim that was not his son. How can the problem be solved?

2

(a)