Inheritance

Worked examples (4)

• 1State what is meant by the term 'allele'
• 2Determine phenotype from a heterozygous genotype
• 3Distinguish between genotype and phenotype
• 4Explain why a recessive allele is not expressed in a heterozygote

Worked examples (4)

• 1State TWO differences between mitosis and meiosis
• 2Explain why meiosis produces genetic variation but mitosis does not
• 3Chromosome number in egg cells
• 4Explain why Down syndrome occurs

Worked examples (4)

• 1Punnett square cross of two heterozygous tall plants
• 2Sex-linked inheritance of colour blindness — sons' genotypes
• 3Explain why blood group AB is an example of codominance
• 4Why sex-linked conditions are more common in males

Worked examples (4)

• 1Explain how antibiotic resistance arises in bacteria
• 2Distinguish continuous and discontinuous variation
• 3Natural selection leading to dark moths in a polluted environment
• 4Explain why selective breeding reduces genetic variation