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 pea plant experiments. Genes — units of inheritance present on chromosomes. Example: Gene for flower color in pea plants. 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 color in pea plants. Recessive Allele — an allele that is masked by a dominant allele. Example: White flower color in pea plants. 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: Passing of traits from parents to offspring
- Gene: Unit of inheritance on chromosomes
- Allele: Different forms of a gene
- Dominant Allele: Always expressed when present
- Recessive Allele: Masked by dominant allele
Common Confusions
- Dominant vs. Recessive Alleles
- Genotype vs. Phenotype
- Homozygous vs. Heterozygous
Typical Exam Questions
- What is a genotype? The genetic makeup of an organism
- What is a phenotype? The physical expression of a trait
- What is the difference between homozygous and heterozygous? Homozygous has identical alleles; heterozygous has different alleles
What Examiners Usually Test
- Understanding of Mendel's experiments
- Ability to use Punnett squares
- Knowledge of dominant and recessive traits