Summary
Inheritance is the process by which traits are passed from parents to offspring. Heredity — the passing of traits from parents to offspring. Example: Mendel's experiments with pea plants. Genes — units of inheritance present on chromosomes. Example: Gene for flower color in peas. Alleles — different forms of a gene. Example: Alleles for purple and white flowers. Dominant allele — an allele that is always expressed when present. Example: Purple flower allele in peas. Recessive allele — an allele that is masked by a dominant allele. Example: White flower allele in peas. Genotype — the genetic makeup of an organism. Example: PP, Pp, or pp for flower color. Phenotype — the physical expression of a trait. Example: Purple or white flowers. Homozygous — having two identical alleles for a trait. Example: PP or pp. Heterozygous — having two different alleles for a trait. Example: Pp.
Exam Tips
Key Definitions to Remember
- Heredity
- Genes
- Alleles
- Dominant and recessive alleles
- Genotype and phenotype
Common Confusions
- Mixing up genotype and phenotype
- Confusing dominant and recessive alleles
Typical Exam Questions
- What is heredity? Heredity is the passing of traits from parents to offspring.
- What is a genotype? Genotype is the genetic makeup of an organism.
- What is a phenotype? Phenotype is the physical expression of a trait.
What Examiners Usually Test
- Understanding of Mendel's experiments
- Ability to use Punnett squares
- Differences between homozygous and heterozygous
