Question

Which among the following is a correct statement regarding pea plants?

• A. A pea plant producing wrinkled seeds has dissimilar alleles for the character seed shape
• B. A pea plant producing violet flowers always has dissimilar alleles for the character of flower colour
• C. A pea plant producing green coloured pods always has similar alleles for the character pod colour
• D. A tall pea plant either has similar or dissimilar alleles for the character of stem height

Answer 1

The correct option is D A tall pea plant either has similar or dissimilar alleles for the character of stem height

Characters are controlled by genes. A gene generally has two alternative forms called alleles, one dominant and one recessive allele.

A diploid organism has two alleles for a specific character.

Dominant allele contains information for the expression of a dominant trait. Dominant traits are expressed when both the alleles are dominant or even when one dominant allele is present. Hence dominant traits are expressed in both homozygous (similar alleles) and heterozygous (dissimilar alleles) conditions.

Recessive allele contains information for the expression of a recessive trait. Recessive traits are expressed only in the presence of two recessive alleles and hence the recessive traits are expressed in homozygous condition only.

Tallness is a dominant trait and hence it is expressed both in homozygous and heterozygous conditions. Hence a tall pea plant has either similar (TT) or dissimilar alleles (Tt) for the character height.

Wrinkled shape of seeds is a recessive trait controlled by recessive alleles. Hence two recessive alleles (similar alleles) are required for the expression of the trait.

Violet colour of flowers and green coloured pods are dominant traits and are expressed both in homozygous and heterozygous conditions.

Hence a plant producing violet flowers and the plant producing green colour pods either has similar or dissimilar alleles.