This study notes covers Key Terms for Genetics within Genetic Inheritance for GCSE Biology. Genetic inheritance patterns, alleles, and inheritance diagrams It is section 1 of 9 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 1 of 9
Practice
25 questions
Recall
25 flashcards
Key Terms for Genetics
The Bossy vs Shy Allele
Dominant alleles are bossy — if one is present, it shows. Capital letter (B).
Recessive alleles are shy — only show up when there's no bossy allele around. Lowercase (b).
Bb = Brown eyes (bossy B wins). bb = Blue eyes (both shy, so blue shows).
| Term | Meaning |
|---|---|
| Dominant | Allele that is always expressed when present (shown with CAPITAL letter, e.g., B) |
| Recessive | Allele only expressed when there's no dominant allele (lowercase, e.g., b) |
| Homozygous | Two identical alleles (BB or bb) |
| Heterozygous | Two different alleles (Bb) |
| Genotype | The alleles an organism has (e.g., Bb) |
| Phenotype | The physical characteristic (e.g., brown eyes) |