Written Biology Test
P generation (Parental) - The a pea plants you Start a cross with(you)
F1 generation (Filial means sons) - offspring of the P generation(kids)
F2 generation - offspring of the F1 generation(grandkids)
Dominant - The stronger trait which overpowers the recessive
Recessive - The weaker trait which will only be expressed in the
absence of a dominant one
Mendel's Theory (the basis of modern genetics):
Parents don't directly pass on traits, they pass on genes (factors) that determine traits.
For each trait, an individual has two genes, one from each parent.
For any trait, the 2 alleles may or may not contain the same information:
Homozygous - both genes have the same inormation
Heterozygous - the a genes contain different information
Allele - The 2 copies of the same gene that we have for every trait one of each is carried on the 2 homozygous chromosomes
Phenotype - your physical appearance determined by the alleles for that trait - (what You Look Like)
Genotype - Your genetic makeup, the set of alleles an individual has/the genes YOU have
Sure, let's break down all this information simply:
- Laws: Mendel formulated two main laws:
- Law of Segregation: Each organism carries two alleles for each trait, and these alleles separate during the formation of gametes (egg and sperm cells).
- Law of Independent Assortment: Alleles for different traits are distributed to gametes independently of one another.
Pea Plant Traits:
- Mendel studied traits like flower color (purple or white), seed shape (round or wrinkled), and pod color (green or yellow).
Ways Traits Are Inherited:
- Regular Dominant-Recessive: One allele is dominant and masks the effect of the recessive allele (e.g., brown eyes dominant over blue eyes).
- Codominant: Both alleles in a pair are fully expressed (e.g., AB blood type).
- Incomplete Dominant: The heterozygous phenotype is a blend of the two homozygous phenotypes (e.g., red and white flowers producing pink flowers).
- Polygenic Inheritance: Traits controlled by multiple genes, resulting in a range of phenotypes (e.g., skin color, height).
- Multiple Alleles: More than two alleles exist for a gene (e.g., ABO blood group system).
- Environmental Influenced: Traits influenced by environmental factors (e.g., height influenced by nutrition).
- X-Linked: Traits carried on the X chromosome, often affecting males more (e.g., hemophilia).