A class used beads to model fertilisation between two heterozygous parents. For each trial, one allele was selected at random from each parent and the modelled offspring was classified by phenotype.
The results from 80 trials are shown in the table.
| Modelled phenotype | Number of trials |
|---|---|
| dominant | 56 |
| recessive | 24 |
Calculate the ratio of dominant to recessive modelled offspring in these trials.
Express it in the form x:1x:1x:1, with x x\,x rounded to the nearest whole number.
186 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.