In Mendel’s experiments, tall pea plants (T) are dominant

Human Evolution (10)

In Mendel’s experiments, tall pea plants (T) are dominant over dwarf pea plants (t).

  1. What is the phenotype and genotype of the F1 generation if a homozygous tall plant is crossed with a homozygous dwarf plant?
  2. Draw a Punnett square board to show the gametes and offspring when both the parents are heterozygous for tallness.
  3. What is the phenotypic ratio and genotypic ratio of the above cross in (ii)?
  4. State Mendel’s Law of Dominance.
  5. What is a Dihybrid Cross?

Answer

(i) Phenotype - All are tall plants

Genotype - All are hybrid / heterozygous dominant

(ii)

(iii) Phenotypic ratio - 3 : 1

Genotypic ratio - 1 : 2 : 1

(iv) Out of a pair of contrasting characters, the one that is expressed is dominant and the one that is not expressed is recessive.

(v) It is breeding plants taking two pairs of contrasting characters.

  • Exam Year: 2019