Mendel's experiments — A/L Biology

How do I practise Mendel's experiments?

1 question with a worked solution

1. In a dihybrid cross between two heterozygous garden pea plants (RrYy × RrYy), what proportion of the F₂ offspring is expected to exhibit the recombinant phenotypes?
   1. A) 1/16
   2. B) 6/16
   3. C) 9/16
   4. D) 10/16
   Check my answer

   Correct answer: B) 6/16

   In Mendel's dihybrid cross, parental phenotypes are round-yellow (9/16) and wrinkled-green (1/16). Recombinant (non-parental) phenotypes are round-green (3/16) and wrinkled-yellow (3/16). Total recombinants = 3/16 + 3/16 = 6/16 (3/8).

   Show worked solution

   Step 1: Classical Mendelian F₂ dihybrid ratio: 9 (Round Yellow) : 3 (Round Green) : 3 (Wrinkled Yellow) : 1 (Wrinkled Green). Step 2: Parental phenotypes: Round Yellow (9) + Wrinkled Green (1) = 10/16. Step 3: Recombinant phenotypes: Round Green (3) + Wrinkled Yellow (3) = 6/16. Answer: 6/16.
   Modelled on: the A/L Biology examination pattern

Get this auto-marked

Next in the syllabus

Where does Mendel's experiments fit in the syllabus?

Year 1 · Term 2