Question

In a homozygous plant round seeds (R) are dominant over wrinkled seeds (r) : 

(i) Draw a Punnett square to show the gametes and offspring when both the plants have heterozygous round seeds (Rr). 

(ii) Mention the Phenotype and Genotype ratios of the offsprings in F2 generation. 

(iii) Name the sex chromosomes in human males and females. 

(iv) Briefly explain the term ‘Mutation’. 

(v) What is the number of chromosomes in the gametes of human beings ?

Answer 1

(i)

R = Dominant Round

r = Recessive wrinkled

(ii) Genotypic ratio – 1:2:1 

1. Homozygous round 

2. Heterozygous round 

3. Homozygous wrinkled Phenotypic ratio = 3:1 

(iii) Human male sex hormone = Testosterone Human female sex hormone = Oesterogen Progesterone. 

(iv) Mutation : The sudden change in one or more genes which changes the hereditary materials of a cell which in turn changes the character of an organism. 

(v) 23.