Monohybrid inheritance

6 Describe heterozygous as having two different alleles of a particular gene

7 State that a heterozygous individual will not be pure-breeding

8 Describe a dominant allele as an allele that is expressed if it is present in the genotype

9 Describe a recessive allele as an allele that is only expressed when there is no dominant allele of the gene present in the genotype

10 Interpret pedigree diagrams for the inheritance of a given characteristic

11 Use genetic diagrams to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1:1 and 3:1 ratios

12 Use Punnett squares in crosses which result in more than one genotype to work out and show the possible different genotypes

13 Explain how to use a test cross to identify an unknown genotype

14 Describe codominance as a situation in which both alleles in heterozygous organisms contribute to the phenotype

15 Explain the inheritance of ABO blood groups: phenotypes are A, B, AB and O blood groups and alleles are Iᴬ, Iᴮ and Iᴼ

16 Describe a sex-linked characteristic as a feature in which the gene responsible is located on a sex chromosome and that makes the characteristic more common in one sex than in the other

17 Describe red-green colour blindness as an example of sex linkage

18 Use genetic diagrams to predict the results of monohybrid crosses involving codominance or sex linkage and calculate phenotypic ratios