Biology Module 5 Flashcards
Alleles
Different forms of the same gene.
Dominant allele
The allele that expresses the trait whenever it is present.
Recessive allele
The allele that expresses the trait only when the dominant allele is not present.
Genotype
The genetic composition of the organism.
Homozygous
Both alleles for a gene are the same (either both dominant or both recessive).
Heterozygous
One allele is dominant and one allele is recessive.
Phenotype
The physical appearances determined by the genes.
Laws of segregation
During gametogenesis, each gamete receives only one allele for every gene.
Dihybrid cross
The results of male and female mating with regard to two traits.
Monohybrid cross
The results of male and female mating with regard to a single trait.
Law of independent assortment
Each allele for a trait moves into the gametes without influencing the other alleles for other traits.
Pedigree
The record of ancestors for an individual (or family) showing parent/offspring relationships across the generations, also called a family tree.
Autosome
A chromosome that does not determine the sex of the individual.
Sex chromosomes
Two chromosomes that determine the sex of an individual.
Sex-linked disorder
A disorder caused by an allele that is found on a sex chromosome.
Mutagen
An agent that causes a genetic mutation.
