Fig. 3.1 shows a pedigree chart for a plant species that may bear blue flowers or purple flowers. Blue flower colour is dominant over purple flower colour. The allele for blue flowers is shown by the letter B. The allele for purple flowers is shown by the letter b. These plants can therefore have genotypes BB or Bb or bb.
(a(i))[3]
State the genotypes of plants 1, 4 and 6 in Fig. 3.1. Plant 1 ………………… Plant 4 ………………… Plant 6 …………………
(a(ii))[3]
Describe how a gardener could use selective breeding to produce plants that only bear blue flowers.
(b)[3]
Complete the Punnett square by entering the flower colours of the parent plants and the genotypes of the offspring. State the phenotypic ratio for this cross.
(c)[3]
Write the correct term beside each definition in Table 3.1.
Worked solution & mark scheme
This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: “genotype of plant 1: Bb” …