Summary
Inheritance in biology involves the transmission of genetic information from parents to offspring, determining traits and characteristics.
- Meiosis — a type of cell division that reduces the chromosome number by half, producing gametes. Example: Sperm and egg cells are formed through meiosis.
- Phenotype — the physical expression of genetic traits. Example: Eye color or blood type.
- Genotype — the genetic makeup of an organism. Example: AA, Aa, or aa for a specific trait.
- Alleles — different versions of the same gene. Example: Alleles for eye color can be blue or brown.
- Recessive allele — an allele that only expresses its trait when two copies are present. Example: Albinism is expressed when both alleles are recessive (aa).
Exam Tips
Key Definitions to Remember
- Meiosis: Cell division that results in gametes with half the chromosome number.
- Phenotype: The observable characteristics of an organism.
- Genotype: The genetic constitution of an organism.
- Alleles: Different forms of a gene.
- Recessive allele: An allele that is expressed only when two copies are present.
Common Confusions
- Confusing meiosis with mitosis, which is for growth and repair.
- Mistaking phenotype for genotype.
Typical Exam Questions
- What is the role of meiosis? It produces gametes with half the chromosome number.
- How does a recessive allele express itself? Only when two copies are present.
- What determines blood group inheritance? The alleles inherited from both parents.
What Examiners Usually Test
- Understanding of meiosis and mitosis differences.
- Ability to distinguish between phenotype and genotype.
- Knowledge of how alleles determine traits.